REAL INSTITUTO Y OBSERVATORIBOLETÍ

XVth IAGAON GEOMAGNETON GEOMAGNETINSTRUMENTS, D

AND PRO

ABSTRACABSTRAC

IO DE LA ARMADA EN SAN FERNANDON ROA No.2/2012

WORKSHOPTIC OBSERVATORYTIC OBSERVATORYDATA ACQUISITIONOCESSING

CT VOLUMEMINISTERIO

DE DEFENSA

CT VOLUME

REAL INSTITUTO Y OBSERVATORIO DE LA ARMADA EN SAN FERNANDO BOLETÍN ROA Nº 2/2012

XVth IAGA WORKSHOP ON GEOMAGNETIC OBSERVATORY INSTRUMENTS, DATA ACQUISITION

AND PROCESSING

ABSTRACT VOLUME

MINISTERIODE DEFENSA

SECRETARÍAGENERALTÉCNICA

© Autor y editor 2012NIPO: 083-12-138-9ISSN: 1131-5040Depósito Legal: CA-469-78Fecha de edición: junio 2012

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CATÁLOGO GENERAL DE PUBLICACIONES OFICIALES

http://www.publicacionesoficiales.boe.es/

XVth IAGA WORKSHOP ON GEOMAGNETIC OBSERVATORY INSTRUMENTS,

DATA ACQUISITION AND PROCESSING

Abstract Volume June 4TH – 14TH, 2012

Royal Institute and Observatory of the Navy San Fernando, Cádiz, Spain.

SPONSORED BY:

Ministry of Economic And Competitiveness

Ministry of Defense

Spanish Navy City of San Fernando

Royal Institute and Observatory

Of the Navy

COMMITTEES AND CONTACTS

International Organizing Committe:

Chairman:

Arnaud Chulliat, Institut de Physique du Globe de Paris, France

Secretary:

Manuel Catalán, Royal Observatory of the Spanish Navy, Spain

Members

Mioara Mandea, Centre National d'Etudes Spatiales, Paris, France

Aude Chambodut , School and Earth Science Observatory (EOST - Strasbourg), France

Jeffrey J. Love, U.S. Geological Survey, USA

Pavel Hejda, Institut of Geophysics of the ASCR, Czech Republic

Pieter Kotze, Hermanus Magnetic Observatory, South Africa

Juan José Curto, Ebro Observatory, Spain

Hans-Joaquim Linthe, GeoForschungsZentrum Postdam, Germany

Christopher W. Turbitt, British Geological Survey, United Kingdom

Local Committee:

J. Martín Dávila

M. Catalán

M. Larrán

J. A. Peña

J. Gallego

 

 

 

   

 

CONTENTS  

SESSION I: ABSOLUTE MEASUREMENTS ........................................ 1  

Auster H.U, and Korte M. (Oral presentation) .................................................................. 3

• Results of Absolute Measurements Performed in the Niemegk Geomagnetic Observatory Using the Di3-flux Instrument.

Gonsette A., and Rasson J. (Oral presentation) ................................................................. 4

• Autodif: a New Step in Development of Automated Magnetic Observatories.

Hegymegi and Csontos et al (Oral presentation) ............................................................... 5

• Results of the Development of Automatic Baseline Controlling Didd (ABCD) Magenotemer.

Korte M. and Brunke HP, et al (Oral presentation) ........................................................... 6

• Status of the Geomagnetic Automated System Gauss. 

Marsal S. and Torta J.M, et al (Oral presentation) ............................................................ 7

• Stability of Variometers in Partly Manned Settlements: Lessons Learnt from Livingston Island Observatory.

Rasson J. (Oral presentation) ............................................................................................. 8

• Accuracy of Our Diflux Measurements and Can We Improve?

Chandra K. and Sannasi S.R. (Poster I-1) ......................................................................... 9

• Comparison Observations for Calibration, and Pillar Correections at Hyderabad Magnetic Observatory.

Hegymegi and Szöllősy J. (Poster I-2) ............................................................................ 10

• Cableless D/I Teodolite with Fluxset Magnetometer.

Maestre B. (Poster I-3) .................................................................................................... 11

• Magnetometers and Magnetostatics.

Matzka J. and Pedersen Lars W....................................................................................... 12

• The Tilting Di-Fluxgate Sensor.

Nagamachi S. and Fukui K (Poster I-5) .......................................................................... 13

• Advanced Method to Estimate Variations of Geomagnetic Baseline Values.

SESSION II: MAGNETOMETERS ....................................................... 14

Brunke HP, and Pulz E. et al (Oral presentation) ............................................................ 16

• Progress with an Optically Pumped Magnetometer (OPC) for the Permanent Recording of the Earth´s Magnetic Field Vector.

Korepanov V. and Marusenkov A. (Oral presentation)................................................... 17

• Flux-Gate Magnetometer Noise Reduction Possibilities.

Marusenkov A. and Korepanov V. et al (Oral presentation) ........................................... 18

• The In-Situ Calibration of the Nurmijarvi Observatory Variometer.

Matzka J. and Pedersen W. et al (Oral presentation)....................................................... 19

• Advancing Geomagnetic Observatory Operations by Near Real-Time One-Second Samples.

Pajunpää K. and Klymovych E. et al (Oral presentation) .............................................. 20

• Modernizing of the Nurmijarvi Magnetometer Calibration System.

Pedersen W. and William L. et al (Oral presentation)..................................................... 21

• Detection of Mechanical Unstability in Di-Fluxgate Sensors.

Brunke H.P. and Bronkalla O. et al (Poster II-1) ............................................................ 22

• Long-Term Experiences with the GFZ K-Tandem Magnetometers and a Comparison of Different Magnetometer Types at the Niemegk Observatory.

Csontos A. (Poster II-2) ................................................................................................... 23

• Methods for Measuring the Gradient of the Magnetic Field Using Standard Observatory Instrumentation.

Heilig B. and Csontos A. et al (Poster II-3) .................................................................... 24

• Measuring the Orthogonality of Coil Systems by Means of a Total Field Magnetometer.

Lalanne A. and Telali B. (Poster II-4) ............................................................................. 25

• Testing Facilities at Chambon La Forêt Magnetic Observatory.

Lim M. and Park Y. et al (Poster II-5) ............................................................................ 26

• Change of Loggers of DZN, GZU, Hos Observatories and Adding of dIdD to GZU, Hos Observatories.

Merényi L. and Heilig B. et al (Poster II-6) .................................................................... 27

• Geomagnetic Data Acquisition System Developed for the Plasmon Project.

Neska M. and Reda J. et al (Poster II-7) .......................................................................... 28

• A New Implementation of Geomagnetic Field Station for Monitoring Purposes.

Pedersen L.W. and Petersen J.R. (Poster II-8) ................................................................ 29

• New Low Noise 1 Hz Fluxgate Electronic for FGM-FGE.

Shanahan T. and Flower S. et al (Poster II-9) ................................................................. 30

• Experiences in Designing a Low Cost, Temperature Controlled Variometer Enclosure.

Suarez S.M. and Wiedeman M. et al (Poster II-10) ........................................................ 31

• Variometer Using a Temperature Stabilized Sensor.

SESSION III: OBSERVATORIES ......................................................... 32

Berarducci A (Oral presentation) .................................................................................... 34

• Upgrades to the Apia Geomagnetic Observatory, Samoa.

Cabrera E. and Turbitt C.W. et al (Oral presentation) ..................................................... 35

• The Upgrade of Base Orcadas Magnetic Observatory.

Curto J.J. and Torta J.M. et al (Oral presentation) .......................................................... 36

• Anthropogenic Noise in Spanish Observatories.

Hejda P. and Horáček J. et al (Oral presentation) ........................................................... 37

• On the Thunderstorm from 10 July 2011 at Magnetic Observatory Budkov.

Isac A. and Linthe H.J. et al (Oral presentation) ............................................................. 38

• The Renewing of Surlari Observatory: Targets and Present Status of ITS Data Quality.

Muneeza M. and Madeeha A. et al (Oral presentation) ................................................... 39

• Establishment of Geomagnetic Observatory at Islamabad and Repeat Station Results from Northern Parts of Pakistan.

Swan A. and Bishop N. et al (Oral presentation) ............................................................ 40

• South Georgia Observatory: Re-Establishing a South Atlantic Magnetic Station.

Velímský J. and Muslim A. et al (Oral presentation) ...................................................... 41

• Geomagnetic Observatory Gan.

Cabrera E. and Riddick J. et al (Poster III-1) ................................................................. 42

• Indigo Project in Argentina.

Camacho E. and Serra J. (Poster III-2) ............................................................................ 43

• A New Geomagnetic Observatory Construction on Merida, Venezuela.

Chambodut A. and Rambolamanana G. et al (Poster III-3) ............................................ 44

• Towards the Reinstallation of Madagascar Magnetic Observatory.

Covisa P. and Tordesillas J.M. et al (Poster III-4) .......................................................... 45

• San Pablo-Toledo (SPT) Geomagnetic Observatory as Member of Intermagnet (1997-2011)..

Park P.G. and Kim W.S. et al (Poster III-5) .................................................................... 46

• Geomagnetic Field Measurements in the Cheongyang (CYG) Observatory in Korea.

Heumez B. and Lalanne X. et al (Poster III-6) ................................................................ 47

• Dalat, Vietnam: The Re-Opening of a Geomagnetic Observatory.

Hojat A. and Ranjbar H. et al (Poster III-7) .................................................................... 48

• The Necessity of Constructing a Geomagnetic Observatory in Kerman Province, Iran.

Iancu L. and Gatej M. et al (Poster III-8) ........................................................................ 49

• Surlari National Geomagnetic Observatory: Its History from the First Measurements to Its Participation in Intermagnet.

Lepidi S. and Pietrolungo M. et al (Poster III-9) ............................................................. 50

• Geomagnetic Field Observations at Terra Nova Bay (Antarctica).

Lipko Y. and Rakhmatulin R. et al (Poster III-10) .......................................................... 51

• Geophysical Complex of ISTP RAS SB for Monitoring of Electromagnetic Fields at High and Middle Latitudes.

Palangio P. and Lepidi S. et al (Poster III-11) ................................................................. 53

• The Realization of a New Geomagnetic Observatory in Central Italy, Replacing L´Aquila Geomagnetic Observatory.

Pinheiro K. (Poster III-12) .............................................................................................. 54

• The New Geomagnetic Network in Brazil 

Siqueira F. and Pinheiro K. (Poster III-13) ..................................................................... 55

• The New Magnetic Observatory in Brazil: Pantanal.

Tordesillas J.M and Covisa P. et al (Poster III-14) ......................................................... 56

• A Century of Magnetic Observations by IGN.

Varghese S. and Lambkin K. et al (Poster III-15) ........................................................... 57

• Geomagnetic Observations and Modelling at Valentia Observatory, Ireland: Current Status.

Wang L. and Crosthwaite P. et al (Poster III-16) ............................................................ 58

• A New Observatory in Western Australia – Analysing the Magnetic Field Differences Between the Old and New Observatory Sites..

SESSION IV: Networks, Surveys, Repeat Stations and Satellites ....... 59  

Chandrasekhar P. and Arora K. et al (Oral presentation) ................................................ 61

• New Observations from Remote Equatorial Stations in the Southernmost Parts of India.

Delipetrev M. and Delipetrov T. et al (Oral presentation) .............................................. 62

• Correlation Between Tectonic Regionalization and Geomagnetic Field of the Republic of Macedonia.

Heilig B. and Vellante M. et al (Oral presentation)......................................................... 63

• Plasmon Emma for Near Real Time Monitoring of the Plasmasphere.

Humbled F. and Rasson J. (Oral presentation) ................................................................ 64

• Magnetic Valley: a Knowledge Transfer Project.

Koryakin D. (Oral presentation) ...................................................................................... 65

• What Does a Survey Company Need from Geomagnetic Observatories for Marine Magnetic Surveys?.

Lalanne A. and Peltier B. et al (Oral presentation) ......................................................... 66

Ottavianelli G. and Floberghagen R. et al (Oral presentation) ........................................ 67

• Plans for the Calibration and Scientific Validation of Swarm Instruments and Products.

Cifuentes G. and Hernández E. (Poster IV-1) ................................................................. 68

• Mexico Magnetic Chart Epoch 2010.0.

Fernández J. and Galán S. (Poster IV-2) ......................................................................... 69

• Spanish Repeat Station Network in 2012.

Gianibelli J.C. (Poster IV-3) ............................................................................................ 70

• The Teams of Geomagnetic Observatories in Argentina.

Gianibelli J.C. and García R. (Poster IV-4) ..................................................................... 71

• The South Atlantic Magnetic Anomaly and the Network of PPM Observatories for Control.

Heilig B. and Collier A. et al (Poster IV-5) ..................................................................... 72

• Plasmon: Pogress During the First Year.

Hérnandez E. and Cifuentes G. (Poster IV-6) ................................................................. 73

• Mexico 2010.0 Geomagnetic Chart: Resources and Alternatives Applied to Analyze the Space and Time Behavior of the Earth Magnetic Field.

Lipko Y. and Rakhmatulin R. et al (Poster IV-7) ............................................................ 74

• Monitorig and Analysis of Spatial-Time Allocation of Baikal Rift Zone Inhomogeneities.

Masci F. and Di Persio M. et al (Poster IV-8) ................................................................. 75

• Magnetic Field Observations Close to the Epicenter of the 2009 L´Aquila Earthquake.

Masci F. (Poster IV-9) ..................................................................................................... 76

• Ulf Magnetic Observations: An Useful Tool to Investigate the Occurrence of Earthquake Precursors?.

Palangio P. and Di Lorenzo C. et al (Poster IV-10) ........................................................ 77

• Time Evolution of Magnetic Noise Over the Past Years at L´Aquila Geomagnetic Observatory.

Paramasivan E. and Sheikbareeth P. et al (Poster IV-11) ............................................... 78

• Secular Variation of Geomagnetic Field at the Indian Equatorial Station, Tirunelveli (TIR).

Reda J. and Heillig B. et al (Poster IV-12) ...................................................................... 79

• A New European Ground Magnetic Observation Network in the Frame of the Plasmon Project.

Sale A. and Siosinamele B. (Poster IV-13) ..................................................................... 80

• Samoa Geomagnetic Observations; Past, Present and Future.

Semenov V. and Vozar J. et al (Poster IV-14) ................................................................ 81

• Diurnal Precession of the Pole of the Effective Magnetospheric Currents According to the Geomagnetic Observatory Data.

Shevtsov B. and Khomutov S. et al (Poster IV-15) ......................................................... 82

• Geomagnetic Observation Network in the East of Russia.

Shirman B. and Rybakov M. (Poster IV-16) ................................................................... 83

• Dead Sea Sinkholes Detection Using Magnetic Method.

Yang D. and He Y. et al (Poster IV-17) .......................................................................... 84

• The Total Field Change Before the Yushu Earthquake and Its Aftershocks.

SESSION V: DATA PROCESSING AND MANAGEMENT .............. 86

Catalán M. and Larrán M. et al (Oral presentation) ........................................................ 87

• Improving Old Magnetic Data Product by Using Comprehensive Models.

Cop R. and Dezeljin D. (Oral presentation) .................................................................... 88

• Transmission of Measuring Data from Geomagnetic Observatory Sinji VRH (Slovenia) in Construction.

Finn A. and Worthington W. et al (Oral presentation) .................................................... 89

• Development of Quasi-Definitive and Adjusted Magnetic Observatory Data at the Us Geological Survey.

Leonhardt R. and Matzka J. (Oral presentation) ............................................................. 90

• Magpy- A Python Based Software for Analyzing Geomagnetic Observatory Measurements.

Linthe HJ. And Reda J. et al (Oral presentation)............................................................. 91

• Observatory Data Quality Check – The Instrument to Ensure Valuable Research.

White T. (Oral presentation) ............................................................................................ 92

• Current Hardware and Software Development for the Usgs.

Chambodut A. and Menvielle (Poster V-1) ..................................................................... 93

• K Indices Statiscal Variations: Between Minute and Second Data.

Dolinský P. and Valach F. et al (Poster V-2) .................................................................. 94

• Accuracy of One-Hour Means of Geomagnetic Element H Having Missing Data.

El-Lemdani F. and Menvielle M. et al (Poster V-3) ........................................................ 95

• A Statiscal Study of LT Variations of aλ Sectorial Geomagnetic Activity Indices.

Nahayo E. and Kotzé P.B. et al (Poster V-4) .................................................................. 96

• Overview of the Stability of Baseline Values for 1-Sec Fluxgate Magnetometer Lemi-025 at Hermanus Observatory.

Nosé M. and Iyemori T. et al (Poster V-5) ...................................................................... 97

• WP Index: A new Substorm Index Derived From High-Resolution Geomagnetic Field Data at Low Latitude.

Turbitt C. and Matzka J. et al (Poster V-6) ..................................................................... 98

• An Instrument Performance and Data Quality Standard for Intermagnet One-Second Data Exchange..

Yao X. and Yang D. et al (Poster V-7) ............................................................................ 99

• The Characteristic of the New Geomagnetic Activity Index VR

SESSION VI: APPLICATIONS ............................................................ 100

Chandrasekhar E. and Prasad P. (Oral presentation) ..................................................... 102

• A Study of Phase Characteristics of Geomagnetic Jerks Using Complex Wavelets.

Chulliat A. (Oral presentation) ...................................................................................... 103

• Geomagnetic Secular Acceleration Analysis from Magnetic Observatory Data.

Gianibelli J.C. and Quaglino N. (Oral presentation) ..................................................... 104

• A Methodology to Detect Calm Days.

Pourbeyranvand S. (Oral presentation) ........................................................................ 105

• A New Method to Reduced the Daily Variation Noise from Geomagnetic Observatory.

Samrock F. and Kuvshinov A. (Oral presentation) ....................................................... 106

• Tippers at Costal and Island Geomagnetic Observatories. A Useful Tool to Probe Electrical Conducitivity of the Earth´s Crust.

Saroso S. and Nuraeni F. et al (Oral presentation) ........................................................ 107

• Some Results of Seismo-Electromagnetic Researchat Lapan, Indonesia.

Gannon J.L. and Finn C.A. et al (Poster VI-1) .............................................................. 108

• Usgs Geomagnetism Program Product Summary.

Gianibelli J.C. (Poster VI-2) .......................................................................................... 109

• Permanent Geomagnetic Observatories Network, IGRF; Geodynamics and Sun-Earth Connection.

Spomenko J. and Cop. R. (Poster VI-3) ........................................................................ 110

• The Structure of Solar-Geomagnetic Disturbances and the Dynamics of Atmosphere.

Tozzi R. and Dominici G. et al (Poster VI-4) ................................................................ 111

• Results of the Development of Automatic Baseline Controlling Didd (ABCD) Magenotemer.

Villasante V. and Casas B. et al (Poster VI-5) .............................................................. 112

• Geomagnetic Monitoring of the 2011-2012 Volcanic Eruption in El Hierro (Canary Islands, Spain)

Wang X.Z and Teng Y.T. et al (Poster VI-6) ................................................................ 113

• Geomagnetic Observation at Meridian Stations in China.

KEYNOTES ............................................................................................. 114

Thomson A. ................................................................................................................... 116

• Space Weather Applications of Geomagnetic Observatory Data.

Korte M. ........................................................................................................................ 117

• New Instrument Developments for Geomagnetic Observatories.

Olsen N. ......................................................................................................................... 118

• Ground Observatories and Satellites-Two Complementary Sources for Exploring the Earth´s Magnetic Field.

 

1

Session I Absolute Measurements

 

3

RESULTS OF ABSOLUTE MEASUREMENTS PERFORMED IN THE NIEMEGK GEOMAGNETIC OBSERVATORY USING THE DI3-FLUX INSTRUMENT

H.U. AUSTER 1, M. Korte 2

1. TU-Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany, uli.auster@tu-bs.de

2. GFZ Potsdam, Section 2.3., Telegrafenberg, 14473 Potsdam, Germany, monika@gfz-potsdam.de

Since 1980 the DI-Flux measurement is the commonly used procedure for determining the Earth's magnetic field components absolutely. The instrument used for this procedure consists of a non-magnetic theodolite equipped with a single axis fluxgate sensor. We replaced the single component fluxgate by a three component sensors which allows the measurement of the full Earth vector at each setting. The additional information can be used to characterise the instrument, to recover measurement errors and to calculate for the first time error bars of an absolute measurement. During the Changchun workshop this advanced method was successfully applied. Since two years measurements with the DI3 Fluxgate have been continuously performed in the Geomagnetic Observatory Niemegk. A comparison to the standard absolute measurement, instrument characteristics and error bars which represent the observation quality will be presented.

4

AUTODIF: A NEW STEP IN DEVELOPMENT OF AUTOMATED MAGNETIC OBSERVATORIES.

ALEXANDRE GONSETTE 1, Jean Rasson 1

1. Royal Meteorological Institute of Belgium, Rue du centre de Physique 3 - 5670 Viroinval, Belgium, agonsett@meteo.be, jrasson@meteo.be

An automated absolute DI measurement is the biggest difficulty to overcome if we want to see unattended observatories deployed through the world. In this way we present here the last developments of our automatic device Autodif. A new prototype similar but sligtly different from that presented in Changchun has been built. It has been put to test during the five first months of this year. The residual method has been chosen to avoid the system to reach exactly the zero position. One measurement set takes about five minutes and is performed every thirty minutes also during the night. An intercomparison between automatic and manual procedure by removing the Autodif from the pillar and replacing it with the traditionnal method is finished. The first results presented some differences with the reference manual measurements but after having removed all the residual magnetic parts in the AUTODIF, these differences fell to less than +-0.005° for D and less than +-0.002° for I. The error analysis tend to attest the good results of the measurements.

5

RESULTS OF THE DEVELOPMENT OF AUTOMATIC BASELINE CONTROLLING DIDD (ABCD) MAGNETOMETER

L. HEGYMEGI 1, A. Csontos 2, B. Heilig 2

1. MinGeo Ltd, H-1142 Budapest, Ráskai L. u. 20, Hungary, hegymegi@elgi.hu 2. Eötvös L. Geophysical Institute, H-1145 Budapest, Columbus u 17-23, Hungary, csontos@elgi.hu, heilig@elgi.hu

dIdD instruments provide absolute value for the length of the geomagnetic field vector but they are variometers for declination and inclination angle however these values are absolute in the coordinate system of the coils. To get declination and inclination angles in the geographic reference frame, in practice absolute measurements are used in the observatories. In the last few years we developed procedures which can be used on an automatic manner to determine the baseline of the dIdD magnetometer by the instrument itself. The development of the ABCD magnetometer is not yet finished but coil orthogonality check and inclination baseline determination was resolved. To test the method we have built and operated a device in Tihany Observatory. In this paper we present the instrument and discuss the latest results.

6

STATUS OF THE GEOMAGNETIC AUTOMATED SYSTEM GAUSS

MONIKA KORTE 1, Heinz-Peter Brunke 1, Eberhard Pulz 1

1. Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany, monika@gfz-potsdsam.de, epulz@gfz-potsdam.de, brunke@gfz-potsdam.de

Geomagnetic observatories have to provide data series that only reflect the natural variations of the Earth's magnetic field and are not influenced by any other factors. This applies in particular to the long-term stability of the data series. However, data from magnetometers recording the geomagnetic field vector often are subject to other influences like e.g. from temperature variations or pillar tilts. Regular absolute vector measurements are mandatory to control the base-lines of the continuously recording magnetometers. While it nowadays is easy to obtain absolute scalar values, e.g. from Overhauser magnetometers, the determination of the absolute directional values remains a task that has to be performed manually and very carefully by means of DI flux theodolite. This requirement hampers the installation of high-quality, automated magnetic observatories in remote regions to fill gaps in the global network. The Geomagnetic AUtomated SyStem GAUSS, developed in a cooperation between GFZ and TU Braunschweig, automatically determines the field intensity in two horizontal directions by means of rotations of a three-axis fluxgate magnetometer. The method allows for a full calibration of the sensor together with total intensity and the normal variation recordings, providing absolute values for all components. The exact orientation of the instrument with regard to a geographic reference frame is controlled by an optical set-up. The GAUSS instrument has been running in a long-term test at the Niemegk observatory since 2008 very reliably with very few mechanical problems. However, the accuracy of the directional results is very sensitive to any changes and requires a highly precise monitoring of the orientation. At present, we have obtained satisfactory results, comparable to the quality of the traditional manual method, for time intervals of several months. However, for some other time intervals we still struggle to understand some unsatisfactorily large scatter in the GAUSS directional results. Here, we report on the latest status in terms of mechanical reliability and output data quality of the instrument.

7

STABILITY OF VARIOMETERS IN PARTLY MANNED SETTLEMENTS: LESSONS LEARNT FROM LIVINGSTON ISLAND OBSERVATORY

S. MARSAL, J.M. Torta, J.J. Curto. 1. Observatori de l’Ebre, (OE), CSIC - Universitat Ramon Llull, Horta Alta 38, E-43520 Roquetes, Spain (smarsal@obsebre.es, jmtorta@obsebre.es, jjcurto@obsebre.es)

Geomagnetic observatories deployed at remote sites, such as in Antarctica, which are only manned during restricted periods of time (e.g. in summer), could still record valuable data throughout the whole year if they are appropriately automated and powered. Assumptions must be made concerning the baselines evolution during the period without absolute control. When different kind of variometers are simultaneously operating and temperature is also recorded, data comparisons help to assess the validity of such assumptions. In this paper, we describe our experiences at Linvingston Island Observatory, LIV (South Shetland Islands, Antarctica), where the two main instruments in the automatic magnetic observatory are a proton vector magnetometer (PVM) designed by the British Geological Survey, made up of a Geomag SM90R Overhauser magnetometer deployed at the centre of a pair of dual axis Helmholtz coils in dIdD configuration, and a suspended tri-axial fluxgate magnetometer (model FGE). It has been revealed that both instruments are sensitive to temperature variations, but in a dynamic way, and differently depending on the magnetic element, though other factors must influence the observed differences as well. Intercomparisons of quiet-day, midnight momentary values from LIV and Argentine Island (AIA), the nearest INTERMAGNET magnetic observatory (i.e. having full absolute control), for the last three years of corrected data available (2008-2010) provide other qualitative and quantitative tests, which support the procedure of using the absolute measurements to reference the PVM data in a first step, and in turn using such PVM ‘semi-definitive’ data to reduce the FGE data in a second step. From these intercomparisons we conclude that the decision to use linear functions to pass from the adopted differences at the end of one survey to those of the beginning of the next one is a suitable compromise.

8

ACCURACY OF OUR DIFLUX MEASUREMENTS AND CAN WE IMPROVE IT?

J. RASSON 1.

1. Institut Royal Météorologique de Belgique, jr@oma.be.

Absolute measurements are at the very base of our observatory data production. Therefore a good understanding and monitoring of the performance and quality of our absolute instruments is necessary. The IAGA observatory workshops adress this concern by organizing periodically (every two years) intercomparison sessions of absolute instrumentation. We will discuss here the Diflux theodolite: the instrument able to perform absolute measurements of the magnetic declination and inclination. The talk will first examine the accuracy limiting factors of a typical Diflux. Based on past experience, we will try to evaluate how those factors may affect the quality of our Diflux measurements. The methods used for improving the Diflux’s accuracy will be mentioned. We will then examine the results of the Difluxes which have measured in past IAGA workshop intercomparison sessions when they have been made available. We will try to extract all useful accuracy information relating to these past intercomparison sessions. We will discuss what can be done for Difluxes/observers which do badly at the intercomparison. Finally we will propose that intercomparison sessions in our IAGA workshops have a more standardised approach and be recorded faithfully in an ad hoc database, possibly coordinated by the IAGA working group V-OBS. One innovation would be that the participating Difluxes be clearly identified together with the operating observers and their Observatory. One idea here is to be able to follow the DIflux instruments over their life and take the necessary steps to improve the failing ones.

9

COMPARISON OBSERVATIONS FOR CALIBRATION, AND PILLAR CORRECTIONS AT HYDERABAD MAGNETIC OBSERVATORY

K. CHANDRA SHAKAR RAO 1, S.R. Sannasi.

1.0N.G.R.I, Habsiguda, Hyderabad, India - 500007.

Hyderabad Magnetic Observatory operated the La Cour analogue suspension system (1964-2011) for 46 years. Baseline values were determined variously at 3 pillars (No. 1, 2 and later 3). Pillar differences were checked every 3 years and inter comparison with Alibag (ABG)-India’s Prime Magnetic Observatory, were carried out every 2-3 years. Baselines on pillar 3 became definitive in 2003. Hyderabad Observatory became IMO in 2008, with 3-component digital fluxgate variometer and GSM-90 Overhauser magnetometer. A new DI-Flux Micrometer Theodolite and PPM were installed on the pillar number 2 in 2009. Subsequently all absolute observations were carried out and reduced to pillar 2. Pillar differences between 3 and 2 for the DFM system were again determined. In 2010, all absolute observations were shifted to pillar 2, after re-determination of pillar corrections. An additional 3-component digital fluxgate variometer (GEOMAG-02M) was installed in May 2011, to provide digital 1-minute back up data. The data from this system was validated against all absolute observations and DFM data and then the analogue La Cour system was discontinued. In view of all the changes made in the past 3 years, in December 2011 a series of absolute experiments carried out with a new GEOMETRICS856AX-PPM, (with 0.5nT accuracy & 0.1nT resolution) and new DI-Flux Micrometer Theodolite (arc 3sec in accuracy) and the old DI-Flux Zeiss-20B Theodolite to check the pillar corrections for ΔF and H, D & Z baseline values from all 3 observatory pillars and reduction of both variation sets to same absolute pillar 2 commenced. The results are presented here. The differences between the pillars have been determined to be < 1nT.

10

CABLELESS D/I TEODOLITE WITH FLUXSET MAGNETOMETER

L. HEGYMEGI 1, J. Szöllősy 2

1. MinGeo Ltd, H-1142 Budapest, Ráskai L. u. 20, Hungary, hegymegi@elgi.hu 2. ARACONSYS LLC, H-1121 Budapest, Konkholy T.M. u. 29-33, Hungary, szollosy@araconsys.hu

At D/I absolute instruments, fluxgate sensor is fixed on the telescope of the teodolite and a cable connects it to the electronics. This (usually long) cable can be effected by external noise sources and makes the observation inconvenient. On our new instrument the fluxset sensor is fixed on one side of the telescope and the electronics with the battery is on the other side. This unit does not contain any display but a large LED display is built into a separate unit. For the connection between the electronics and the display, a radio link is used. Both units can be charged from 12 V DC or from 100-240 V AC. The new instrument was tested in Tihany Observatory and the results are presented on the poster.

11

MAGNETOMETERS AND MAGNETOSTATICS

B. MAESTRE 1

1. Sanakorp Group, C/ Alejandro Hidalgo 3. Las Palmas de Gran Canaria, Spain, bernardo.maestre@sanakorp.com

This article summarizes the current proton precession magnetometer and Overhauser performing the analysis of nuclear Overhauser enhancement through the cross-relaxation. Squid and vsm are detailed even aren't portable which are appreciated new techniques for measuring the magnetization as complementary measures. Finally is developed a chapter covering the electromagnetic analysis that bases the previous principles analyzing the magnetic dipole and its relationship to the magnetostatic. It is necessary to detail the demagnetizing field as an intermediate step for the understanding the magnetostatic energy and magnetic work essential to the techniques described.

12

THE TILTING DI-FLUXGATE SENSOR J. MATZKA 1, Lars W. Pedersen 1 1. DTU Space, National Space Institute, Technical University of Denmark, Juliane Maries Vej 30, 2100 Copenhagen, Denmark We observed a great disagreement for the sensor offset of some Pandect fluxgate sensors when determined by different methods. At first, a number of possible explanations were discussed: 1) Errors in the procedures or instruments involved in the determination of the sensor offset. 2) Technical problems with the sensors, for example an induced or remanent magnetic impurity. 3) Vertical tilting of the sensor holder arrangement during D I measurements. To test for the third option, we slightly extended the theory for the DI-fluxgate to include a tilting angle for the sensor during the measurements as a further parameter, the sign of the tilting angle depending on the telescope position (sensor up or sensor down). In fact, the tilting sensor theory could predict the observed disagreement for the sensor offset. Based on this theory, we developed several procedures to test for a tilting sensor on a DI-flux. Examination of the sensors with a tilting problem showed that this behaviour was not caused by the sensor holder arrangement, but a loose ferromagnetic core inside the fluxgate sensor.

13

ADVANCED METHOD TO ESTIMATE VARIATIONS OF GEOMAGNETIC BASELINE VALUES

K. Fukui 1, S. NAGAMACHI 1

1. Kakioka Magnetic Observatory JMA, 595 Kakioka Ibaraki-ken Ishioka-shi, Japan

With respect to the absolute geomagnetic observations, we need to estimate the variation of baseline value from previous observation to judge the most recent observation is good or bad. In Kakioka Magnetic Observatory (KMO), if the difference between observed baseline value and estimated baseline value is within 0.3nT or 0.03’, we regard the observation is good. In order to estimate the baseline values, we have used simple extrapolation of past data. But this method is not sufficient in case intervals of absolute observations are long. So we take absolute observations more frequently than weekly. We detect that tilts of magnetometer’s sensor and underground temperature effect geomagnetic field data, and develop a new method considering these major factors to estimate variations of baseline values. In this presentation, we report the new method to estimate the variations of geomagnetic baseline values. We evaluate performance of the method that it makes possible to examine the quality of recent absolute observations even in case intervals of absolute observations are bi-weekly.

14

Session II Magnetometers

 

16

PROGRESS WITH AN OPTICALLY PUMPED MAGNETOMETER (OPC) FOR THE PERMANENT RECORDING OF THE EARTH’S MAGNETIC FIELD VECTOR

H.-P. BRUNKE 1, E. Pulz 1, O. Bronkalla 1 1.Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany, brunke@gfz-potsdam.de During the last Workshop for Geomagnetic Observatory Instruments, Data Acquisition and Processing in 2010, we reported about an optically pumped magnetometer for the permanent recording of the Earth's magnetic field vector. The aim of this development was to have an instrument which provides a complete set of vector recordings every second in near absolute quality. During the last two years we made several modifications to improve mainly the temperature dependence of this instrument. We designed a new marble coil system and installed an optical system to monitor the orientation with respect to the geographic reference frame. Now we can determine the H-component absolutely by means of a rotation of the coil system. Moreover, we can orient the system in the true north direction by means of a fine angular scale in comparison to the standard observatory recordings. We are working on controlling the absolute orientation by means of an optical system. We report about the modifications of the instrument and the remaining problems, and we present recent data series in comparison to the standard Niemegk observatory recordings.

17

FLUX-GATE MAGNETOMETER NOISE REDUCTION POSSIBILITIES

V. KOREPANOV 1, A. Marusenkov 1

1. Lviv Centre of Institute for Space Research, 5A Naukova St., 79060 Lviv, Ukraine, vakor@isr.lviv.ua

Recent requirements for the observatory magnetometers, specifically, to change 1-minute INTERMAGNET standard to 1-second one, demand to lower their magnetic noise level (NL). As observatory magnetometer the flux-gate magnetometer (FGM) is used everywhere. For the moment, regular NL of such magnetometers is about 0.1 – 0.01 nT in best case, what is not enough for 1-second standard. Because of this the problem to decrease NL to satisfy these new requirements is very actual one. It is the authors’ opinion confirmed by numerous experiments, that the FGM NL is determined not by Barkhausen jumps during the core re-magnetization from positive to negative state as the majority of designers believe, but by non-repeatability of the magnetic domains transition from negative to positive states and back. This shows the way how to reduce the magnetic noise: to manufacture the magnetic material with a structure which will create conditions for magnetic domain walls to glide easily and uniformly when changing their orientation leading to minimal efforts at cyclic re-magnetization. Ideally, such a material may be represented as a “solid liquid” with freely floating uniform magnetic domains without walls friction. To approach to such a state as much as possible, the best results gives the magnetic materials annealing in any inert gas applying by this during all annealing time the alternative magnetic field. If to accept the “solid liquid” model, the obtained NL decreasing has clear physical explanation: permanent movement of domains leads to the structural improvements favorable namely for the homogenization of transitions, rise of temperature gives necessary energy for the impurities liquidation. A new effect of further NL decrease was revealed in space experiments: the magnetometer NL started to decrease and lowered by ~ 20-30% with time. This effect was investigated and it was named “gamma-magnetic normalization”. Its physical mechanism and possible use for further decrease of FGM NL are discussed. The present research was partially supported by SSAU contract 1-05/08.

18

THE IN-SITU CALIBRATION OF THE NURMIJARVI OBSERVATORY VARIOMETER

A. MARUSENKOV 1, V. Korepanov 1, K. Pajunpää 2

1. Lviv Centre of Institute for Space Research, 5A Naukova St., 79060 Lviv, Ukraine, marand@isr.lviv.ua

2. Finnish Meteorological Institute, Nurmijärvi Geophysical Observatory, Observatoriontie 125 FIN-05100 Röykkä, Finland, Kari.Pajunpaa@fmi.fi

The attempt to calibrate in-situ the observatory variometer without its regular operation interruption was performed. For this purpose, the comparison of its records of the same magnetic field recorded simultaneously by a reference magnetometer was exploited. The low-noise flux-gate magnetometer LEMI-025 was used as a reference instrument. It was calibrated in the three-component Calibration Coil (CC) system, which magnetic axes were aligned to the geographical frame. Keeping the same tilt of the reference sensor respectively horizontal plane during the calibration procedure in CC and at further records of the geomagnetic variations and applying data of the absolute measurements allowed us to know the exact orientation of the reference sensor axes respectively the geographic frame. After the CC calibration the magnetometer LEMI-025 has been installed in the variometer hut of the observatory close to the main variometer and more than two weeks of records were acquired. The data for last 9 days only, when the baseline of the reference magnetometer had stabilized, were analyzed and processed. The scale factors, the sensor components non-orthogonality and orientation errors and the noise level of the observatory magnetometer were estimated. Due to enough long record time and few geo-magnetically disturbed days rather low level of the methodical errors (0.1 % for scale factors and 0.1 deg. of arc for non-orthogonality and orientation angles) had been achieved.The peculiarities of the data processing as well as the calibration procedure outcomes are presented in the report. The present research was partially supported by STCU project 5567.

19

ADVANCING GEOMAGNETIC OBSERVATORY OPERATIONS BY NEAR REAL-TIME ONE-SECOND SAMPLES

J. MATZKA1, L. W. Pedersen1, O Bjerregaard Hansen1, L. Tøffner-Clausen1, C. Stolle1 1. DTU Space, National Space Institute, Technical University of Denmark, Juliane Maries Vej 30, 2100 Copenhagen, Denmark.

DTU Space has recently introduced a near real-time transfer for one-second samples from the geomagnetic observatories BFE, NAQ, GDH, and THL as well as for 13 variometer stations. The transfer is handled by programs originally developed for other geophysical data from Greenland. Then, the data is converted to daily files in cdf-format that hold the raw variometer values, baselines, scale values and flags and form the basis of our data treatment. This concept turned out to be very useful. For the calculation of baselines we traditionally use one-second samples. The one-second samples and their first differences turned out to be advantageous for automatic and visual spike detection and for comparison with neighbouring stations to efficiently distinguish spikes from natural variations. One particular success is that we are for the first time able to detect systematic timekeeping errors by our observers during the absolute measurements. Another case is the NAQ observatory: the difference plot between the main and back-up variometer showed times of distinctive noise. By analysing one-second samples we are for the first time able to identify which one of the two variometers actually is noisy during these times. The great advantage over our previous data transfer system (for which one-second samples were only available with delay and extra effort), is that we now can react to problems in the observatories immediately. Unfortunately, we find artificial noise in our recordings that exceeds the variometer noise even for the most remote locations.

20

MODERNIZING OF THE NURMIJARVI MAGNETOMETER CALIBRATION SYSTEM

K. PAJUNPÄÄ 1, E. Klymovych 2, J. Rynö 1, A. Prystaj 2

1. Finnish Meteorological Institute, Nurmijärvi Geophysical Observatory,

Observatoriontie 125 FIN-05100 Röykkä, Finland, kari.pajunpaa@fmi.fi 2. Lviv Centre of Institute for Space Research, 5A Naukova St., 79060 Lviv, Ukraine,

pristaj@isr.lviv.ua The three-component magnetometer calibration system at the Nurmijärvi Geophysical Observatory has served for calibration of satellite and geophysical magnetometers for couple of decades. This calibration system is the only known accredited by European metrological community what gives confidence to high reliability of its calibration results. The electronics that was made in 1990's suffered of out-of-date components and was therefore modernized in 2010-2011 by a joint team of Nurmijärvi Geophysical Observatory and Lviv Centre of Institute for Space Research. The modernized system is based on electronic components that communicate through a local computer network. Computer dependent hardware is no more needed. The system components were carefully calibrated and the measurement uncertainty was estimated to further meet the requirements of the accreditation. The capability of the system and first calibrations results will be presented.

21

DETECTION OF MECHANICAL UNSTABILITY IN DI-FLUXGATE SENSORS.

PEDERSEN, LARS WILLIAM 1, Matzka, Jürgen 1

1. DTU Space, Juliane Maries Vej 30, Denmark, lawp@space.dtu.dk, jrgm@space.dtu.dk

An important part of the DI measurement with the teodolite is to calculate the sensor parameters (horizontal misalignment, vertical misalignment, sensor offset) to see, if the sensor is stable over time.It is important to track these parameters over time, since the sensor need to be stable to give correct DI results. The Danish Met. Institute and now DTU Space have during many years produced DI fluxgate electronics and use fluxgate sensors from Pandect. Some years ago several of the sensors from Pandect were unstable, and it turned out to be a problem with loose ferromagnetic cores in the sensor, so the angle (or misalignment) change when the sensor was turned ’upside down’ during the DI measurement. We have found a way to glue the ferromagnetic cores within the new sensors to make them mechanical stable. All sensors are tested very carefully before use. In the workshop the sensor is placed in a ’zero field’ cylinder and the offset (sensor offset + electronic offset) is ajusted to within +-2nT. In the observatory, a careful DI measurement is then made, and if the ferromagnetic core is tilting during the procedure when the telescope is inverted, this results in an erroneously high sensor offset value. By comparing the sensor offset determined by zero field (true value) and DI (erroneous value), loose ferromagnetic cores can be detected. Since the observed erroneous sensor offset values due to loose sensors were extremely high, we use a fast methode (called ’double offset’) for a first check of the sensors: In one of the ’I’-positions (e. g. north up) the residual is adjusted to zero (0.0nT) and the sensor it turned by exactly 180.0000 degrees from ’up’ to ’down’. The residual reading on the electronic should now give 2 times the offset that would be determined during a complete I measurement. It is not a’waterproof’ methode, but it was used with succes in China a few years ago to find bad sensors.

22

LONG-TERM EXPERIENCES WITH THE GFZ K-TANDEM MAGNETOMETERS AND A COMPARISON OF DIFFERENT MAGNETOMETER TYPES AT THE NIEMEGK OBSERVATORY

H.-P. BRUNKE 1, O. Bronkalla 1, H.-J. Linthe 1, M. Korte 1, E. Pulz 1

1. Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany, brunke@gfz-potsdam.de At the Niemegk Observatory many magnetometers are operated in parallel. There is the main observatory system consisting of a 3-axis fluxgate and an Overhauser proton magnetometer. At least two additional backup systems are continuously run in parallel. Moreover, there are three optically pumped scalar K-magnetometers, using the tandem principle, which were developed at GFZ during the 1990ies. Another optically pumped magnetometer is operated in vector mode using additional fields applied by a coil system. A whole bunch of other instruments deliver data for test purposes. Comparison of all available data allows to assess noise and long term stability of single instruments. A common interpretation can be obtained from the multitude of measured field values. Disturbances to certain instruments can be identified. The total reliability can be improved. The combination of all data leads to an expected value of the magnetic field with less noise compared to recordings of each single instrument. We report on the experiences with the long-term comparison of the K-magnetometers to other scalar magnetometers. Moreover, we sketch an automated software system for a common interpretation of several magnetometers of different types.

23

METHODS FOR MEASURING THE GRADIENT OF THE MAGNETIC FIELD USING STANDARD OBSERVATORY INSTRUMENTATION

A. CSONTOS 1,

1. Eötvös L. Geophysical Institute, Tihany Geophysical Observatory, Hungary, csontos@elgi.hu The direction and the intensity of geomagnetic elements are measured in many ways in current observatory practice. Several of the methods implicitly suppose that the magnetic field is homogeneous, i.e. the spatial gradient of the field is constant. The observers try to keep away the recording instruments from strong magnetic anomalies to reach the best result. (The degradation of the proton signal of a proton magnetometer caused by high magnetic gradient is well known.) However, there are a few phenomena (for instance the sea-side effect) which create special circumstances for the measurements (e.g. the spatial differences of the geomagnetic elements vary in time). In that case the accuracy of the absolute control of variometers is decreased, because the base values of a variometer become dependent on the external influences. The gradiometers based on nuclear magnetometers are ideal for measuring moderate total field gradient and its evolution in time. Standard observatory instrumentation gives further chance to identify any change of the magnetic gradient. The poster presents methods based on standard instruments and gives real examples for measuring the variation of magnetic gradient.

24

MEASURING THE ORTHOGONALITY OF COIL SYSTEMS BY MEANS OF A TOTAL FIELD MAGNETOMETER

B. HEILIG 1, A. Csontos 1, K. Pajunpää 2

1. Tihany Geophysical Observatory, Tihany, Hungary, heilig@elgi.hu 2. Finnish Meteorological Institute, Nurmijärvi, Finland, kari.pajunpaa@fmi.fi

Recently, a simple method was published for the determination of the pitch angle between two coil axes by means of a total field magnetometer. This method is applicable when the homogeneous volume inside the coils is large enough to accommodate the sensor of a total field magnetometer. The orthogonality of calibration coil systems used for calibration of vector magnetometers can be calibrated by this procedure. In addition, the method can be easily automated and applied for the calibration of delta inclination–delta declination (dIdD) magnetometers. The method was tested by 3 different research groups at different geomagnetic observatories (NUR, Finland, 2nd; THY, Hungary). The instrumentation was also not identical. This paper summarizes the test results and discusses the limitations of the method.

25

TESTING FACILITIES AT CHAMBON LA FORÊT MAGNETIC OBSERVATORY.

A. LALANNE 1, B. Telali 1

1. Institut de Physique du Globe de Paris, 1 rue Jussieu, 75238 Paris cedex 05, France, lalanne@ipgp.fr, telali@ipgp.fr

The French national magnetic observatory is located in Chambon la Forêt, 100 km South of Paris, in a large forest, far from human or industrial activities. This observatory is also acting as a calibration site. Several systems sufficiently disseminated to prevent interferences are available and frequently used by academic users, space agencies or private companies for instrument testing. The major equipments are listed below: 3-axis field simulator with separate DC and AC coils placed in Helmholtz configuration. DC coils are around 3 meter wide. Each coil system is operated by a current amplifier with DC-15 KHz band pass. The coil system is drive by a computer and 3 synchronized 16-bit DA converters allowing simulating a large variety of magnetic profile including those observed by magnetometers installed in flying objects. A 2-layer Mumetal magnetic shielded room offering a 2 x 2 x 2 m inner volume. The DC attenuation factor is about 3x10-3 in the entire volume. Smaller magnetic shielded boxes are also available for sensors noise measurements. A large temperature controlled steel free test room (5.5x2.3x2 m) with 2 sensors pillars. This test room is used to qualify the temperature coefficient of the sensor and its electronics placed in the same environment which is our common mode of operation. A computer controlled system is used to adjust and maintain the temperature in the -5 to +45°C range.

26

CHANGE OF LOGGERS OF DZN, GZU, HOS OBSERVATORIES AND ADDING OF dIdD TO GZU, HOS OBSERVATORIES

MUTAEK LIM 1, Y. Park 1, Y. Shin 1, H. Rim 1

1. Korea Institute of Geoscience & Mineral Resources, limmt@kigam.re.kr

The loggers of the three observatories DZN, GZU and HOS were changed from Flare+ of BGS to MagRec-4 of MinGeo Co. The later provides us remote access and control through internet so that the management of the observatories will become more effective and more timely. For the GZU and HOS observatories, we will add a suspended dIdD magnetometer GSM-90F5D to each observatory so that we construct a data set for each observatory free from artificial noises utilizing the existing observatory data and the newly added dIdD magnetometer data in the same time.

.

27

GEOMAGNETIC DATA ACQUISITION SYSTEM DEVELOPED FOR THE PLASMON PROJECT

L. MERÉNYI 1, B. Heilig1, L. Szabados1

1. Eötvös Loránd Geophysical Institute, Budapest, Hungary, merenyi@elgi.hu

We present the geomagnetic data acquisition system that is developed to fulfill the requirements of pulsation stations of the PLASMON project. Hardware parts to be presented include the selected magnetometer types, A/D converter, data acquisition electronics, embedded computers, GPS unit and power supply elements. The software of the system includes a DOS program used as a real-time interface to the A/D converter, and a Linux system with a graphical data acquisition program. We discuss some practical issues related to file formats, network configurations, near real-time data transmission and remote attendance. Some test results are presented for estimated noise and settling time of the magnetometer signals, A/D conversion and digital filtering, and for estimated timing accuracy of the sampling.

28

A NEW IMPLEMENTATION OF GEOMAGNETIC FIELD STATION FOR MONITORING PURPOSES

M. NESKA 1, J. Reda 1, K. Nowozynski 1, P. Czubak 1

1. Institute of Geophysics, Polish Academy of Sciences, ul. Ksiecia Janusza 64, 01-452 Warsaw, Poland, nemar@igf.edu.pl

We present the technical and operation description of a new type of geomagnetic field station providing features like installation for long-term usage, continuous recording, and real-time data access basing on GSM network. This type of station enables a monitoring of the magnetosphere in the frame of the PLASMON project of the EU (FP7 – SPACE).

29

NEW LOW NOISE 1 Hz FLUXGATE ELECTRONIC FOR FGM-FGE.

L.W. PEDERSEN 1, J.R. Petersen 2.

1 DTU Space, Juliane Maries Vej 30, Denmark, lawp@space.dtu.dk, janr@space.dtu.dk

DTU Space has started the process of developing a new electronic for the FGM-FGE 3-axial fluxgate magnetometer, so the instrument in the future can fulfill the new INTERMAGNET 1 sec. standard. The aim of the work will be to produce a new magnetometer electronic, that can replace existing FGE electronics without changing sensors and cabling and can be used the same way as before with same analog and digital output and stability, but with better data quality. On the poster, we will show the latest progress of the development and some of the ideas we have to improve the instrument.

30

EXPERIENCES IN DESIGNING A LOW COST, TEMPERATURE CONTROLLED VARIOMETER ENCLOSURE

T. SHANAHAN 1, S. Flower 1, C. Turbitt 1

1. British Geological Survey, West Mains Road, Edinburgh, EH9 3LA, UK

Magnetic observatories have traditionally used small buildings or huts to provide a stable, protected and temperature controlled environment to accommodate the sensitive magnetic instruments. As instruments have evolved they have reduced in size and become less reliant on absolute mechanical stability but still require good temperature stability. Maintaining a stable temperature in large older buildings can be difficult and expensive due to their volume, the substantial thermal losses and undefined thermal properties of the construction materials. This report describes a modern instrument housing comprising a small-scale enclosure and low-power, non-magnetic heating elements controlled by a proportional–integral–derivative (PID) temperature controller. Operating magnetometers in a compact environment with other equipment requires careful selection of heating elements and minimising any sources of local interference. The specifications and calculations for the enclosure design, materials and temperature control system are presented with results of long term temperature stability performance in comparison with traditional observatory housings. The disadvantages and benefits of operating instruments in small enclosures are also discussed.

31

VARIOMETER USING A TEMPERATURE STABILIZED SENSOR

S.M. SUAREZ 1, M. Wiedemann 1, R. Kroth 1

1. Magson GmbH, Carl Scheele Strasse 14, 12489 Berlin, Germany, sandra.suarez@magson.de

Avoiding thermal drifts can be achieved by using material with low thermal expansion coefficient or by keeping the sensor in a thermally stabilized environment. Since our sensor has a very low thermal capacity (consist of 25g aluminium and copper only) the second option has been selected particularly for magnetic field measurements under harsh environmental conditions. Due to its uniform expansion characteristics we are able to operate the sensor in a wide temperature range. Especially for space applications it has been qualified between -100°C up to 200°C. Nevertheless rapid temperature changes (e.g. during eclipses) might influences the measurement results. For that reason we have developed a heater system for controlling the sensor thermally. The digital fluxgate technique permits a synchronised heating which allows the cancellation of magnetic stray field generated by the heater. The heat power is due to the low mass and small volumes of the sensor less than 1W. Furthermore the instrument has a network interface for remote controlling of heater and all other parameters as well as for analysing data online. Measurement results and instrument characteristics will be presented.

32

Session III Observatories

 

34

UPGRADES TO THE APIA GEOMAGNETIC OBSERVATORY, SAMOA

ALAN BERARDUCCI 1

1. Compass Rose Surveying, Inc., 5080 Fall River Road, Idaho Springs, Colorado 80452, USA, Berarducci@att.net

A project to upgrade the Apia geomagnetic observatory (IAGA code API) was undertaken in October and November 2011. Improvements include additional infrastructure to house new variometer and total field magnetometers, and a new data logger with an internet-based data transmission system. API is now equipped with a Danish FGE variometer in a temperature-controlled hut, a Quanterra data logger, a GSM-90 overhauser magnetometer, and a DTU Model G with a Zeiss 020 theodolite DI-Flux. H, D, Z, and F components are logged as one second data and transmitted in near real time to New Zealand, USA, and Intermagnet. The project was funded by ETH Zurich with critical support from GNS Science (New Zealand) and the Geomagnetism Program of the US Geological Survey. API is one of the oldest continuously operated geomagnetic observatories in the Pacific and provides a 110-year time series of geomagnetic data for researchers around the world. The closest observatories to API are Pamatai, French Polynesia, 2400 km; Eyrewell, New Zealand 3600 km; Honolulu, Hawaii, 4200 km; and Charter Towers, Australia, 4500 km. The project plan, infrastructure construction, magnetometers, data loggers, examples of data plots, and baselines will be presented.

35

THE UPGRADE OF BASE ORCADAS MAGNETIC OBSERVATORY E. Cabrera 1, C. W. Turbitt 2, J. RASSON 3, J. Gianibelli 4, J. Riddick 1. National Weather Service, Observatorio Central Buenos Aires, Av. de los

Constituyentes 3454 (CP 1427, Buenos Aires, Argentina 2. British Geological Survey, Murchison House, West Mains Road, Edinburgh, EH9

3LA, United Kingdom. c.turbitt@bgs.ac.uk, 3. Institut Royal Météorologique, Centre de Physique du Globe, B-5670 Dourbes,

Belgium. jr@oma.be. 4. Head of the Geomagnetism and Aeronomy at the UNLP, Argentina. In January 2012 new absolute magnetometers, fluxgate variometers and recording hardware to monitor and record changes in the Earth’s magnetic field have been installed at Base Orcadas Observatory, in a collaborative project between the Argentine National Weather Service (SMN), the British Geological Survey (BGS) in Edinburgh and the Institut Royal Météorologique de Belgique, Dourbes as part of the INTERMAGNET Digital Geomagnetic Observatory (INDIGO) program. This observatory is located on the Argentine Antarctic Base on the South Orkney Islands (Orcadas del Sur), with the new equipment replacing existing photographic recording equipment which was damaged by an earthquake in 2003. The equipment is designed to meet INTERMAGNET standards for data quality providing a one-minute data set which will be corrected to absolute through a program of absolute observations. The original magnetic observatory at Base Orcadas (the oldest in Antartica) was installed by the Scottish National Antarctic Expedition in (SNAE) 1902-04 and recordings of variations in the Earth’s magnetic field have continued since that time at this remote location

36

ANTHROPOGENIC NOISE IN SPANISH OBSERVATORIES

J.J. CURTO 1, J.M. Torta 1, S. Marsal 1, M. Catalán 2, P. Covisa 3.

1. Observatori de l’Ebre, (OE), CSIC - Universitat Ramon Llull, Horta Alta 38, E-43520 Roquetes, Spain (jjcurto@obsebre.es, jmtorta@obsebre.es, smarsal@obsebre.es) 2. Real Instituto y Observatorio de la Armada, San Fernando 11100, Spain (mcatalan@roa.es) 3. Observatorio Geofísico de Toledo (IGN), Carretera de Ávila km 3,5 Toledo, Spain (pcovisa@fomento.es)

Although geomagnetic observatories are intended to measure natural magnetic fields, very often their records are polluted by “artificial” fields, mainly caused by the action of men and their technology. With the progressive advance of the civilization, observatories had to move to remote places in an exodus which has not finished yet because new settlements are taking place where it was a virgin area. Roads but especially electrified railway lines and power lines are the dominant sources of noise. We will talk about the experience of the Spanish observatories dealing with anthropogenic noise.

37

ON THE THUNDERSTORM FROM 10 JULY 2011 AT MAGNETIC OBSERVATORY BUDKOV

P. HEJDA, J. Horáček, M. Vlk, T. Bayer

1.- Institute of Geophysics of the ASCR, Boční II/1401, 14131 Prague, Czech Republic, ph@ig.cas.cz

The region around Geomagnetic Observatory Budkov suffers from strong thunderstorms. For example, in 1994 the newly installed digital magnetometer CANMOS was, in spite of the installed lightning protection modules, severely injured by lightning. Since then all the data links were replaced by optical cables and the same security measures were adopted in the case of installation of the second digital system, GDAS. Frequent outage of the main voltage during storms was solved by sufficient battery capacity. Extremely strong storm occurred on 10 July 2011, when a lightning stroke a larch at the observatory. Summit of the larch was broken away and the trunk was split. Various electric and electronic components were damaged. Fortunately, GDAS magnetometer kept working. It showed out that all three components recorded jumps in their values: ~ 5 nT (1 min arc) in D, 2 nT in H and 0.5 nT in Z. The jumps in D and H were later confirmed also by absolute measurements. We suppose that the sensor skipped and turned slightly due to the quakes caused by the thunder and falling tree.

38

THE RENEWING OF SURLARI OBSERVATORY: TARGETS AND PRESENT STATUS OF ITS DATA QUALITY

A. ISAC 1, H.-J. Linthe 2, M. Mandea 3, L. Iancu 1

1. Geological Institute of Romania, 1 Caransebes str., Sector 1, Bucharest, RO-012271, Romania, margoisac@yahoo.com 2. GeoForschungsZentrum Potsdam, Telegrafenberg D-14473 Potsdam, Germany, linthe@gfz-potsdam.de 3. Centre National d'Etudes Spatiale, 2 Place Maurice Quentin, 75039 Paris, France, mioara.mandea@cnes.fr

Since 2009 Surlari observatory has entered in a new era, with almost completely new instrumentation and devoted people with the needed skills to operate it. Then, realistic targets have been set up for measurements accuracy, stability, and for a sensible attitude to data logging, processing and quality control. The absolute measurements are performed with a Geometrics G856 proton magnetometer and a DI-Flux theodolite THEO 010B equipped with a Bartington fluxgate magnetometer MAG01H, three – four times a week, to monitor the instrumental drift of three operating variometers (a FGE produced by the Danish Meteorological Institute-the main observatory instrument of high stability and reliability, a Polish torsion photoelectric magnetometer PSM and a British magnetometer Bartington MAG-03). An Overhauser proton magnetometer GSM90 completes the pair of absolute instruments in Surlari observatory. The skills of the new entrants and their dedication have dramatically improved the accuracy of the baselines determination (less than 2 nT), due to a proper procedure and care. The stability of the three variometers is evaluated via their base-lines plotted for all recorded components. The available variometers are also subject of systematic inter-comparisons in order to detect eventual problems of one of them. Indeed, we are able to identify an instrument which may behave differently, showing a problem as base-line jump, drift, internal or external perturbations or even scale value errors. With the use of scalar F recording independently of a vector magnetometer, and the use of modern data processing software, an immediate quality control is carried out by the delta-F checking. The spikes, jumps or drifts are removed the day after. Statistical analyzes of practical aspects of Surlari variometers operation and the behavior of base-lines for the last four years is presented.

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ESTABLISHMENT OF GEOMAGNETIC OBSERVATORY AT ISLAMABAD AND REPEAT STATION RESULTS FROM NORTHERN PARTS OF PAKISTAN

MUNEEZA M. ALI 1, Madeeha A. 1, Ghulam Murtaza 1, Jean L. Rasson 2

1. Pakistan Space & Upper Atmosphere Research Commission (SUPARCO), muneezamali@gmail.com 2.0Royal Meteorological Institute (IRM) of Belgium, jr@oma.be

After the installation of geomagnetic observatory “Abdus Salam” in Sonmiani (South-west of Pakistan), Pakistan established another geomagnetic observatory at Islamabad (33.75°N, 72.87°E), located in the North-east mountainous region of the country. Since Pakistan is spread along 23-40°N, 60-80°E, the newly established observatory will provide enhanced coverage of geomagnetic activity in the country. During 2008, repeat station work at three selected sites (Multan, Gilgit & Skardu) was also carried out to compare with the survey work previously done during 2005. All this activity was the result of collaboration between SUPARCO and IRM started in 2006 and which culminated in July 2008 by this joint installation and measurement campaign. Experiences during establishment of the observatory and repeat station comparisons/results are described in this study.

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SOUTH GEORGIA OBSERVATORY: RE-ESTABLISHING A SOUTH ATLANTIC MAGNETIC STATION

A. SWAN 1, N. Bishop 2, S. Flower 1, T. Harris 1, T. Shanahan 1, C. Turbitt1

1. British Geological Survey, West Mains Rd., Edinburgh, EH9 3LA, United Kingdom. 2.oNCB Solutions Ltd, Stanley, FIQQ IZZ, Falkland Islands Between 1975 and 1982, British Antarctic Survey (BAS) made absolute magnetic recordings at King Edward Point on the South Atlantic observatory of South Georgia. With few observatories in the region and the proximity to the South Atlantic Anomaly, British Geological Survey (BGS) took the decision in 2009 to re-establish an absolute observatory on South Georgia. Little of the original observatory infrastructure remained so it has not been possible to continue the original SGE data series. However, with assistance of BAS, the South Georgia Government and Cable & Wireless, BGS installed a new observatory (KEP) at the same site during the austral summers of 2010 & 2011; beginning continuous, absolute recordings in March 2011. Here we describe the logistics of the project, along with the observatory buildings and instruments. We also present the results of data recorded over the first year of operation.

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GEOMAGNETIC OBSERVATORY GAN

J. VELÍMSKÝ 1,4, A. Muslim 2, A. Jackson 1, A. Kuvshinov 1, F. Samrock 1, K. Arora 3, K.C.S. Rao 3, L. Pedersen 5, C. Finlay 5, J. Riddick

1. Institut für Geophysik, ETH Zürich, Switzerland 2. Gan Meteorological Office, Dept. of Meteorology, Republic of Maldives 3. National Geophysical Research Institute, Hyderabad, India 4. Dept. of Geophysics, Charles University in Prague, Czech Republic 5. National Space Institute, Technical University of Denmark The geomagnetic observatory GAN was established in April 2011 as a joint project of ETH Zurich, Gan Meteorological Office, and NGRI Hyderabad. The observatory is located at the Gan International Airport on Gan, the southernmost island of the Addu Atoll and the entire Maldives archipelago (73°09'13.47" E,00°41'40.55" S). The new establishment thus considerably improves the spatial coverage of the geomagnetic observatory network in the Indian ocean. The nearest Intermagnet observatories are ABG and HYB at the Indian subcontinent, more than 2000 km to the north, and AAE in east Africa, almost 4000 km to the West. Other observatories in the vicinity are TIR at the southern tip of India, PLB and TUN in Indonesia, and a newly established CKI at the Cocos (Keeling) Islands. The setup of the observatory prioritizes simplicity, low power consumption, and maintenance-free operations while satisfying Intermagnet standards for 1 minute data. The observatory is equipped with a DMI FGM-FGE triaxial suspended fluxgate variometer in HDZ orientation, and a Gemsys GSM-90F1 Overhauser scalar magnetometer. The sensors are placed in separate glassfiber boxes with styrofoam insulation, standing on concrete pillars in concrete/glassfiber semi-open huts, providing shade and allowing for free air circulation. Daily temperature variations in the variometer hut do not exceed 1°C. Power supply consists of a solar panel, a battery backup, and a charge/discharge regulator, the total power consumption of the observatory remains below 15 W. Part of the autonomous system is a miniature PC with linux OS and custom-made software, which transfers the recorded data to the nearby office using Wi-Fi link. A separate absolute hut has a Mingeo 020 declinometer/inclinometer with DMI fluxgate sensor placed on a concrete pillar. Regular absolute measurements started in September 2011 with approx. 1 week periodicity. While we are still addressing issues with long-term drift between scalar and vector instruments, as well as occasional spikes, the observatory is now operational and will be sustained at least for the duration of ESA Swarm satellite mission, and hopefully beyond.

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INDIGO PROJECT IN ARGENTINA

E. CABRERA 1, J. Riddick 2, J. Rasson 2, J.C. Gianibelli 3

1. Servicio Meteorologico Nacional, 25 de Mayo 658, CABA, República Argentina, geof_jef@yahoo.com.ar 2. INTERMAGNET, john_riddick@hotmail.com, jeanrasson@gmail.com 3. Departamento de Geomagnetismo y Aeronomía, Facultad de Ciencias Astronómicas y Geofisicas, UNLP, Paseo del bosque, 1900 La Plata, Argentina, geofisicogianibelli@yahoo.com.ar

In this paper we present the INDIGO Project (INtermagnet DIgital Geomagnetic Observatory) highlights from the National Meteorological Service Vision. The changes on administration, logistics and academic staff are described. The results obtained from the experience in the facilities of the Pilar and Orcadas Observatories are analyzed for future applications in developing countries.

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A NEW GEOMAGNETIC OBSERVATORY CONSTRUCTION ON MERIDA, VENEZUELA

E. CAMACHO 1, J. Serra 2

1. Centro de Investigaciones de Astronomía (CIDA), Mérida, Venezuela, edwincmch@cida.ve 2. Centro de Investigaciones de Astronomía (CIDA), Mérida, Venezuela, jserra@cida.ve A new geomagnetic observatory has been constructed on Mérida (8°33'N, 71°19'O, 1755m). The observatory consists of three wood houses free of magnetic materials, two houses of 3 by 3 meters and one of 3 by 6 meters, also has two external pillars, these facilities are already built. The observatory site it is far enough from man-made disturbances and have an horizontal and vertical gradient is less that 1 nT/m. All construction has been carried out under the recommendations of IAGA "Guide for magnetic measurements and observatory practice". The observatory instruments consists of one GSM v7.0 High Sensitivity Overhauser dIdD Magnetic Observatory System, one GSM-90F1 v7.0 Overhauser Observatory Magnetometer, one Bartington Mag-01H fluxgate declinometer/Inclinimeter and two GSM-19T v7.0 Standar Proton Magnetometer. In next months we hope to have the observatory 100% operational, only left to install communication system, power system, and instruments. On the other hand, measurements of the geomagnetic field have been taken with the GSM-90F1 magnetometer since June 2011 in a site next to the observatory buildings, but with a bit of noise, also in next weeks we will begin to take base line measurements.

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TOWARDS THE REINSTALLATION OF MADAGASCAR MAGNETIC OBSERVATORY

A. CHAMBODUT 1, G. Rambolamanana 2, M. Rambolamanana 2, IOGA Technical Team 2, L.M. Razafindranaivo 2, F.N. Ranaivo-Nomenjanahary 2, M.Menvielle 3,4

1. EOST, Dep. of Magnetic Observatories; IPGS, CNRS-INSU UMR 7516, Strasbourg, France, aude@unistra.fr 2. IOGA, Antananarivo, Madagascar 3. Université de Versailles St-Quentin; LATMOS-IPSL, CNRS-INSU UMR 8190, Guyancourt, France 4. Université de Paris-Sud, Département des Sciences de la Terre, Orsay, France. The magnetic observatory of Madagascar (IAGA code: TAN) opened in 1889. Up to now, it was located on the Ambohidempona hill, close to the university campus. Operated by the geomagnetic department of the Institut et Observatoire Géophysique d'Antananarivo (I.O.G.A.), formerly Tananarive observatory, in close cooperation with Ecole et Observatoire des Sciences de la Terre (E.O.S.T.), the TAN magnetic observatory joined the INTERMAGNET Program in 1993. After several periods of major failures due to hard climatic conditions, a huge lightning destroyed the entire acquisition chain (from sensors/instruments to computers) in 2008. In May 2011, a French mission in Antananarivo was organized as part of the collaboration between IOGA and EOST, in order to fully assess the situation of the observatory. It appeared impossible to maintain the magnetic observatory at his historical location because of the growing urbanization. A new site was thus defined and, thanks to IOGA team, construction work was undertaken. Construction of the variometer vault was completed in autumn 2011. A gradual relocation of the observatory will be undertaken over the period 2012-2013.

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SAN PABLO-TOLEDO (SPT) GEOMAGNETIC OBSERVATORY AS MEMBER OF INTERMAGNET (1997-2011).

P. COVISA 1, J.M. Tordesillas 1, V. Marin 1, S. Galán 1, I. Socias 1, J. Fernandez 1.

1. Instituto Geográfico Nacional (IGN), Observatorio Geofísico, 45005 Toledo, Spain, (observatorio.sanpablo@fomento.es)

The geomagnetic observatory of San Pablo-Toledo was joined to the Intermagnet network in 1997. The variometer system Geomag M390 and Vector Magnetometer with “Catalan coil” were recording H, D and Z components of the Earth magnetic field from 1997 up to 2002. The Fluxgate magnetometer FGE model G with tilt compensation was the main system for period 2003-2011. The DI-flux (theodolite Zeiss theo 010B with fluxgate sensor MAG-01H Bartington) and overhauser magnetometers have been used to measure absolute values every week. The paper presents the baselines values of the fluxgate magnetometers and the comparison between variometer systems. As well, it´s described our contribution to the magnetic field monitoring in near real-time at Intermagnet Web site, with each hour variation data and quasi-definitive data.

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GEOMAGNETIC FIELD MEASUREMENTS IN THE CHEONGYANG (CYG) OBSERVATORY IN KOREA

PO GYU PARK 1, Wan-Seop Kim 1, Sung-Dae Hong 2 and Myeong-Son Yu 2

1. Center for Electricity and Magnetism, Korea Research Institute of Standards and Science (KRISS), pgpark@kriss.re.kr. 2. Earthquake Policy Division, Korea Meteorological Administration (KMA)

The Cheongyang (CYG) geomagnetic observatory operating by the Korea Meteorological Administration (KMA) has been built to measure the geomagnetic field and to research prediction of earthquake and space weather. The exact coordinates of the plinths and the azimuth of the target mark determined by a GPS system are 126o 51′ 28″, 36o 21′ 56″ and 148o 17′ 05″, respectively. The target mark is about 1.2 km away from the absolute pillar. The difference in total intensity between the scalar and the absolute pillar was determined using Cs-4He optical pumping magnetometer. Since 10 Dec. 2009, the total intensity and 3 components of geomagnetic field have been measured in 1-s period using the proton and the 3-axis fluxgate magnetometers. In addition, declination (D) and inclination (I) measurements were carried out using the theodolite. Mean values of the D/I measurements were to be D = -8.376 grad, I = 58.423 grad. Then, the components of the baseline determined from the total field and the D/I measurements. However, the measurement results obtained by the proton magnetometer deviate from that measured by the 3-axis fluxgate magnetometer. To reduce this deviation, the scale factor of the fluxgate was readjusted, which, in turn, leads to change the baselines as follows: Xbase, Ybase and Zbase changes from 30200.6 nT to 30203.5 nT, from -3613.5 nT to -3517.3 nT and from 38571.8 nT to 38265.2 nT, respectively. Recently, the installed variometer and electronics were replaced by the new ones because the sudden steps observed in the measured X and Y components did not recover to the original state. After replacement, the noise level of the measured data is significantly reduced and the difference in the total field measured by the proton and the 3-axis fluxgate magnetometers is considerably diminished from 5 nT to 2 nT. The measurement conditions and the measured data obtained by the new sensor almost have fulfilled the requirements needed to join INTERMAGNET. We already submitted a membership application form to join in the INTERMAGNET in 2011.

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DALAT, VIETNAM: THE RE-OPENING OF A GEOMAGNETIC OBSERVATORY B. HEUMEZ 1, X. Lalanne 1, J. Savary 1, A. Chulliat 1, A. Peltier 1 1. Institut de Physique du Globe de Paris, 1, rue Jussieu - 75238 Paris cedex 05,

France, email: heumez@ipgp.fr

The Dalat observatory (IAGA code DLT) has been reinstalled. It is situated in the south of Vietnam, at 1040Km to the South of Phu Thuy (PHU), an INTERMAGNET geomagnetic observatory producing vector data sampled every second. The Dalat observatory was first opened in 1981 but regularly suffered from local thunderstorms. Following almost eight years of inactivity, new equipment was installed and training was delivered to observers for absolute measurements in April 2011. Dalat represents an important site for magnetic measurements. The latitudinal distribution of the two Vietnamese observatories is well suited to studying the diurnal geomagnetic variations and the equatorial electrojet, which flows along the nearby geomagnetic dip-equator. This paper presents how the Dalat observatory was built and improved over time, how the local staff was trained and how the equipment was set up to deliver real-time data sampled every second. After a year of recording, the quality of the baseline is evaluated based upon the usual INTERMAGNET criteria, and by comparing the baseline-corrected data against satellite data. Finally, a comparison with the data quality from other remote geomagnetic observatories is presented.

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THE NECESSITY OF CONSTRUCTING A GEOMAGNETIC OBSERVATORY IN KERMAN PROVINCE, IRAN

A. HOJAT 1, H. Ranjbar 1, S. Karimi-Nasab 1, L. Namaki 4, M. Montahaei 5

1. Assistant Professor, Department of Mining Engineering, Shahid Bahonar University of Kerman, Kerman, Iran, ahojat@uk.ac.ir 2. Ph.D. of Geophysics, Lecturer at Sanandaj Azad University, Kordestan, Iran, loghman_namaki@yahoo.com 3. Ph.D. of Geophysics, Iran, mmontaha@ut.ac.ir

A continuous long-term monitoring of the earth’s magnetic field is being carried out in many observatories all over the world. Despite the large area of Iran, there is only one geomagnetic observatory in the city of Tehran. This observatory is located at the latitude of 35° 44′ 17.5″ and longitude of 51° 23′ 6.4″. However, Tehran city has been considerably expanded in the last decade. This has introduced many noises into the data recorded in this observatory. Kerman province with an area of 180,726 km2 is the second largest province out of the 31 provinces of Iran. It is located in the southeast of Iran and is one of the richest provinces from mineral deposits point of view. This paper discusses the necessity of constructing new geomagnetic observatories in Iran, especially in Kerman province. Due to the exceptional geological characteristics of this area and considering the many applications of observatory data, it is strongly recommended to carry out technical site selection studies to select the optimum site for the construction of a geomagnetic observatory in Kerman province. After construction of a geomagnetic observatory in this region, an increasingly amount of data will be available for the scientists to carry out a variety of geological and geophysical studies.

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SURLARI NATIONAL GEOMAGNETIC OBSERVATORY: ITS HISTORY FROM THE FIRST MEASUREMENTS TO ITS PARTICIPATION IN INTERMAGNET

L. IANCU 1, M. Gatej 1, A. Isac 1, M. Mandea 2, H.-J. Linthe 3

1. Geological Institute of Romania, 1 Caransebes str., Sector 1, Bucharest, RO-012271, Romania, luminita_iancu84@yahoo.com 2. Centre National d'Etudes Spatiale, 2 Place Maurice Quentin, 75039 Paris, France, mioara.mandea@cnes.fr 3. GeoForschungsZentrum Potsdam , Telegrafenberg D-14473 Potsdam, Germany, linthe@gfz-potsdam.de

Surlari National Geomagnetic Observatory (SNGO) is as a part of global magnetic observatory network since 1943. A long collaboration has started since then between Surlari Observatory and Adolf Schmidt Geomagnetic Observatory Niemegk. The construction was supervised by Richard Bock and the Surlari observatory has continuously operated a classical set of photographic magnetographs Askania and Mating & Wiesenberg, made in Potsdam. Research carried out at the observatory has largely contributed to the Romanian geosciences field. Since 1998, Surlari observatory is an IMO (INTERMAGNET observatory). Unfortunately, in 2006 the basic equipment of the observatory has been affected by significant physical and moral wear, especially under the context of rapidly developing technologies and of high performance acquisition process, and for that the observatory risked to be excluded from the community of reference international stations. After a couple of years, in the frame of an international cooperation, the Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences has supported the Geological Institute of Romania to upgrade the Romanian observatory for the up-to-date INTERMAGNET standard. The evolution of the instrumentation and data quality in the Surlari Observatory, over nearly seven decades, is presented. Also, the geomagnetic field behavior during this period is shown, as a characteristic for this region of the world.

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GEOMAGNETIC FIELD OBSERVATIONS AT TERRA NOVA BAY (ANTARCTICA)

S. LEPIDI 1, M. Pietrolungo 1, L. Cafarella 1, L. Santarelli 1

1. Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy, stefania.lepidi@ingv.it

During the 1986-87 austral summer a geomagnetic observatory was installed at the Italian Antarctic Base Mario Zucchelli Station (TNB, geographic coordinates: 74.7S, 164.1E; corrected geomagnetic coordinates: 80.0S, 307.7E; magnetic local time MLT=UT-8). In the first years the measurements of the geomagnetic field were carried out only during summer expeditions. Since 1991 the recording was implemented with an automatic acquisition system operating through the year. In this work we will present the most relevant results obtained from TNB observations coming from more than twenty years of observations, also including a comparison with measurements taken at other Antarctic stations.

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GEOPHYSICAL COMPLEX OF ISTP RAS SB FOR MONITORING OF ELECTROMAGNETIC FIELDS AT HIGH AND MIDDLE LATITUDES

Y. LIPKO 1, R. Rakhmatulin 1, A. Potapov 1, A. Pashinin 1

1. Institute of Solar-Terrestrial Physics RAS SB, 126 Lermontov str., Irkutsk, 664033, Russia, lipko@iszf.irk.ru

The Institute of Solar-Terrestrial Physics RAS SB (Russia, Irkutsk) has got a hardware-software complex for monitoring of electromagnetic fields at high and middle latitudes. This complex includes the following observation stations: 1. Magnetic Observatory “Irkutsk”, founded in 1886, is dedicated to experimental investigation into the Earth’s magnetic field by continuous three-component registration of both absolute values and variations of the geomagnetic field in the frequency range between 0 and 5 Hz. The observatory is equipped with the following magnetometric instruments: the flux-gate declinometer-inclinometer for measurement of declination and inclination, the proton overhouse effect magnetometer for measurement of the total vector, and the three-component flux-gate magnetometer for registration of H, D, and Z component variations. 2. Norilsk Complex Magneto-ionospheric Station is situated on the north of Krasnoyarsk region, and it has worked since 1962. At this station, there is a vast complex of geophysical instruments for absolute and variational observations of the Earth’s magnetic field. This complex includes a declinometer-inclinometer, a three-component flux-gate magnetometer, and a proton overhouse effect magnetometer. Registration of geomagnetic pulsations is carried out using the induction nanoteslameter with 30 Hz sampling frequency of three channel scanning. Moreover, at this station there is a digital ionosonde, an oblique sounding station, an LFM sonde, and a cosmic ray station. 3. Baikal Magneto-Telluric Observatory “Uzur” located on island Olkhon (lake Baikal, 350 km from Irkutsk) has worked since 1962. Continuous twenty-four-hour all-the-year-round observations of low-frequency horizontal electric fields (telluric current, 0.001–10.0 Hz frequency range) and three-component measurements of magnetic components of geomagnetic pulsations (induction nanoteslameter, 0.001–10.0 Hz frequency range), are performed at this station. Furthermore, measurements of vertical component of electric field of geomagnetic pulsations are realized under special programs (vertical measuring line is in Baikal waters). In this report, some scientific results, obtained from observational materials at these observatories, are presented. In this part, the reconstructed secular variation is described of H, D, Z components of the Earth’s magnetic field according to the data of the oldest Siberian Magnetic Observatory “Irkutsk”. The results are shown of the unique

52

experiment on registration of six components (three electric and three magnetic ones) of the Earth’s electromagnetic field (Baikal Magneto-Telluric Observatory “Uzur”). Besides, some extraordinary scientific results of synchronous registration of geomagnetic pulsations and variations of ionosphere parameters in auroral latitudes are stated here (Norilsk station).

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THE REALIZATION OF A NEW GEOMAGNETIC OBSERVATORY IN CENTRAL ITALY, REPLACING L'AQUILA GEOMAGNETIC OBSERVATORY

P. Palangio 1, S. LEPIDI 1, M. Pietrolungo 1, F. Biasini 1, M. Di Persio 1, M. Di Savino 1, C. Gizzi 1, L. Macera 1, F. Masci 1, L. Santarelli 1, U. Villante 2, A. Meloni 1

1. Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy, paolo.palangio@ingv.it 2. Università degli Studi di L’Aquila, L’Aquila, Italy, umberto.villante@univaq.it

The geomagnetic Observatory of L'Aquila (Italy) was founded by INGV in 1958, on the occasion of the International Geophysical Year. It is the main Italian geomagnetic observatory and since 1999 belongs to the Intermagnet network. In 2009 L’Aquila was struck by a strong earthquake; the old town was seriously damaged, and since then many activities moved to the suburbs; close to the Geomagnetic Observatory new activities are planned. Then the necessity to find in the surroundings a new place, suitable for the installation of a Geomagnetic Observatory, arose. Several tests were conducted, and a good location was found in Castel Del Monte, about 40 km from L’Aquila; the preliminary analysis of the electromagnetic background noise and of the spatial (vertical and horizontal) magnetic field gradients has shown that the place well meets the requirements for a Geomagnetic Observatory. The planned observatory consists of a main building for data acquisition and power and four smaller buildings for different geomagnetic instruments.

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THE NEW GEOMAGNETIC NETWORK IN BRAZIL

K. PINHEIRO 1

1. Observatório Nacional - Brazil, Rua General José Cristino, 77, São Cristóvão, Rio de Janeiro, Brazil. Email: kpinheiro@on.br.

The distribution of magnetic observatories at the Earth’s surface is uneven, especially in the South America where only few observatories are part of the INTERMAGNET (International Real-time Magnetic Observatory Network). In this work I will present the plans of the National Observatory to install seven new observatories in Brazil well distributed geographically and following the quality pattern established by INTERMAGNET. The first magnetic observatory is being installed in Pantanal (Mato Grosso), in collaboration with GFZ- Potsdam and SESC-Pantanal. In addition, I will present the current dataset of the repeat stations in Brazil and the project for future reoccupations. With the installation of the new observatories and stations we aim to contribute to the global network of geomagnetic data and better understand the causes and effects of geomagnetic phenomena occurring in Brazil, as the Equatorial Electrojet and the South Atlantic Magnetic Anomaly (SAMA). The SAMA is the region where the intensity of the magnetic field is the weakest of the globe. There are suggestions that the SAMA is caused by reverse flux patches at the core-mantle boundary. However, there is still much debate about its cause and the effects it may cause on the Earth’s surface.

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THE NEW MAGNETIC OBSERVATORY IN BRAZIL: PANTANAL

F. SIQUEIRA 1, K. Pinheiro 1

1. Observatório Nacional - Brazil, Rua General José Cristino, 77, São Cristóvão, Rio de Janeiro, Brazil. Email: fillipe@on.br.

In this work we present a new magnetic observatory in Brazil, located in Pantanal (Mato Grosso State). The reason to choose this location was that Pantanal is close to the center of the South Atlantic Magnetic Anomaly (SAMA) and to the equatorial electrojet (EE). These geomagnetic phenomena are not totally understood on the scientific community. We aim to contribute to the dataset in this region and consequently for a better understanding of the SAMA and EE. Pantanal Observatory is being constructed in colaboration with GFZ- Potsdam and SESC- Pantanal. In this work we discuss all the steps of the installation of Pantanal observatory including the gradiometer survey, test of materials used for the construction and trainning of local staff. We present an illustrated manual that we use to teach and to assist the staff on the absolute measurements. We show the first results obtained from the Pantanal station, installed before the observatory started to work. We compare the geomagnetic storm of 24-25 October (2001) with the data of other observatories in different geographical locations.

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A CENTURY OF MAGNETIC OBSERVATIONS BY IGN

J.M. TORDESILLAS 1, P. Covisa 1, V.M. Cabrera 1, I. Socias 1, V. Marín 1, J. Fernández 1, S. Galán 1

1. Instituto Geográfico Nacional, C/ General Ibáñez Ibero 3, 28003, Madrid, Spain, geomagnetismo@ign.es

In 1912 the Instituto Geográfico Nacional (IGN) began the first magnetic survey of Spain in order to produce the Magnetic Map. The observatories used as reference for this work were Ebro (Society of Jesus) and San Fernando (ROA). From 1934 IGN operates their own geomagnetic observatories. The first one was stablished in Toledo, in the center of Spain, and then the number of observatories working simultaneously increased until five distributed over the Iberian Peninsula, Canary Islands and Fernando Pó in the Gulf of Guinea. At present IGN has two geomagnetic observatories regularly running on the Spanish territory: San Pablo-Toledo (SPT) and Güímar-Tenerife (GUI) that replaced Toledo observatory in 1982 and Tenerife observatory in 1993 respectively. Both of them are equipped with digital equipment and are members of Intermagnet since 1997. As well, IGN has a network of magnetic repeat stations distributed across Spain. In some locations the series of measurements exceed 50 years. This network has been updated since 2000 and is used for the compilation of Spanish magnetic maps (IGN is in charge of this matter), and to contribute in the International Geomagnetic Reference Field and the Magnetic Network European (MagNetE).

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GEOMAGNETIC OBSERVATIONS AND MODELLING AT VALENTIA OBSERVATORY, IRELAND: CURRENT STATUS

SAJI VARGHESE 1, K. Lambkin 1, M. Crean 1 and P. Kotze 2

1. Valentia Observatory, Irish Met Service, Caherciveen, Co. Kerry, Ireland. 2. SANSA Space Science, Hermanus Magnetic Observatory, South Africa. Valentia Geophysical and Meteorological Observatory is located at the south-western extreme of the island of Ireland on the Iveragh peninsula in County Kerry, approximately 1 km south-west of the town of Caherciveen. Magnetic records for the observatory dates back to 1888 and has shown a change in declination from 22 degrees west of True North in 1900 to less than 6 degrees in 2011. Valentia Observatory is the only magnetic observatory in Ireland. Two independent absolute huts are maintained on site. Both use a theodilote mounted DI-fluxgate magnetometer (DI-flux), one with a GEM Systems GSM-19 Overhauser magnetometer and the other a GSM-90. Variometer readings are made by three component Fluxgate Variometers DMI Model FGE ver.G (suspended version), with MinGeo data acquisition. The observatory also completes a national repeat station survey of the Island of Ireland every two years. The Irish secular variation model was recently updated. It is well known that secular change is a comparatively local phenomenon and that it does not proceed in a regular and uniform pattern all over the Earth, giving rise to regions where the field changes more rapidly than elsewhere. Regional field models are derived to describe the geomagnetic field across a limited region of the Earth’s surface primarily because they provide a far better representation in comparison to global models like the IGRF. Polynomial models are among the most frequently used empirical models for curve fitting and to determine the parameters that have a profound effect on a particular response function. They have a simple form, have well known and understood properties, have moderate flexibility of shapes, and they are computationally easy to use. Following this technique, the secular variation model was developed based on a main field model of Ireland using repeat station and satellite data. The results of the new Irish model and an analysis of recent trends in magnetic observations will be presented.

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A NEW OBSERVATORY IN WESTERN AUSTRALIA – ANALYSING THE MAGNETIC FIELD DIFFERENCES BETWEEN THE OLD AND NEW OBSERVATORY SITES

LIEJUN WANG 1, Peter Crosthwaite, Adrian Hitchman, Bill Jones, Andrew Lewis

1 Geomagnetism Section, Geoscience Australia, Canberra, ACT 2601, Australia, geomag@ga.gov.au

Gnangara (GNA) geomagnetic observatory is an INTERMAGNET observatory that supplies K indices to various global indices and radio and space services. It has been in operation near Perth, Western Australia, since 1957. The city of Perth has grown considerably over the intervening 50 years and, while once GNA was remote from urban activity, the observatory is now close to Perth’s outer residential and industrial suburbs. A new geomagnetic observatory has recently been established near Gingin (GNG), 70km from Perth, as a successor to GNA. To ensure a smooth observatory changeover, GNG will run in parallel with GNA for approximately 12 months to study the differences and similarities between the magnetic fields at the two observatories.We have examined magnetic field variations on quiet and disturbed days and found that the horizontal component variations at both sites are nearly the same at night time and are a few nT different during the day. In contrast, GNA has enhanced Z component variations with amplitude up to a few tens of nT greater than GNG, although the two sites are only 50 km apart. To investigate these differences, the magnetic field variations have been modelled using an EM induction method as in magnetotellurics: Horizontal magnetic transfer functions were calculated between GNA and GNG in the frequency domain from periods of 4 minutes to 27 hours to examine amplitudes and phases of the X, Y and Z components at each observatory. The amplitude coefficients are nearly 1 and the phase lags nearly zero between X(GNG) and X(GNA), and Y(GNG) and Y(GNA), across the frequency bands, indicating that the X and Y variations are relatively uniform at these two sites. Therefore K indices scaled from the horizontal magnetic components at two observatories will be similar, with perhaps only minor differences in amplitude of fluctuations over a three-hour interval. Vertical magnetic transfer functions Tzx and Tzy derived from Z = TzxX and TzyY show there are electromagnetic induction effects that affect the Z components, perhaps due to local deviations from a layered conductivity structure. 2D modeling of the transfer functions suggests GNA is located near a boundary of resistive and conductive structures while GNG is away from the boundary and on layered structures. The variations of Z, and any associated with Z (like F), at GNG are reduced in amplitude compared to GNA.This poster will present and discuss these results.

59

Session IV Networks, Surveys, Repeat

Stations and Satellites

 

61

NEW OBSERVATIONS FROM REMOTE EQUATORIAL STATIONS IN THE SOUTHERNMOST PARTS OF INDIA

P. Chandrasekhar, K. Arora, N. Nagarajan 1

1. CSIR-NGRI, Hyderabad-500 007, India

The southern most parts of India provide a unique geographical locale to record magnetic variations that are influenced by Equatorial ionospheric variability in terms of latitudinal and longitudinal spread, as well as strongly affected by ocean induction. While there have been observations from the southern most parts of the mainland, near KanyaKumari, 780 E, (1958-1998), measurements in the Nicobar Islands, 930 E, further east, as well as south of the dip equator were not attempted due to logistic and administrative restrictions. As part of an effort, to study ionospheric variability and estimate of induction in 3-d structure of the Andaman Arc, we have established remote measurement sites at Port Blair (PBL, 110 37.690’N and 920 42.536’E ) and Nicobar (CBY, 070 01.149’N and 930 55.585’E ) and KanyaKumari (VEN, 080 15.631’ N and 770 10.977’E). During the year 2004, due to the Sumatra earthquake and Indian Ocean Tsunami, the Great Nicobar Island, straddling the dip equator, suffered severe damage and after re-building infrastructure, it was possible to increase geophysical monitoring on the island and a magnetometer station, could be established at Campbell Bay (CBY), Great Nicobar, in 2010. Acquiring and retrieving data from CBY continues to be a logistic challenge. At present, about 10 months of concurrent data (2010-2012) from the 3 sites have been obtained and compared and some features of daily variability noted for both quiet and disturbed days. From our recent observations, the EEJ strength is maximum at CBY (~ 140 nT) when compared to VEN (~ 85 nT). Moreover the effect of southward component of interplanetary magnetic field (Bz) is witnessed at both the electrojet sites during the CEJ days; it’s impact appears to be more prominent at VEN rather than at CBY. The recorded CEJ events between VEN and CBY show the longitudinal variability associated with ionospheric irregularities. The effect of other interplanetary parameters (Solar wind speed, Dynamic pressure and electrons released) is studied during the occurrence of solar flares and magnetic storms for the discussed stations. The observations presented here, additionally, form the basis of comparing modelled induced response of 3-d ocean-cum-crustal conductivity with observed variability of the geomagnetic field. Preliminary regional computations show significant anomalies in the vicinity of the Andaman Arc.

62

CORRELATION BETWEEN TECTONIC REGIONALIZATION AND GEOMAGNETIC FIELD OF THE REPUBLIC OF MACEDONIA

M. DELIPETREV 1, Todor Delipetrov 1, Blagica Doneva 1 1. University "Goce Delcev", Faculty of natural and technical science, department of geology and geophysics, St „ Goce Delcev” No.7, Stip, Macedonia, delipetrov@yahoo.com, todor.delipetrov@ugd.edu.mk, blagica.doneva@ugd.edu.mk

The paper presents the maps and the models of the normal geomagnetic field elements for the epoch 1990. Also, it gives the map of tectonic regionalization with brief explanation of geological structure of the terrain. Map of the anomalous vertical component ΔZ of the geomagnetic field is presented. It was made qualitative correlation between the tectonic regionalization and the field of vertical anomalous component ΔZ. Series of geomagnetic anomalies clearly showed the extension of profound faults which are borders between the tectonic units. In the western part dominate negative value of the anomalous vertical ΔZ component with relatively quiet field related to the central and eastern part of the Republic of Macedonia.

63

PLASMON EMMA FOR NEAR REAL TIME MONITORING OF THE PLASMASPHERE

B. HEILIG 1, M. Vellante 2, J. Reda 3, T. Raita 4, P. Sutcliffe 5, L. Merényi 1, A. Csontos 1, P. Kovács 1,

1. Eötvös L. Geophysical Institute, Budapest, Hungary, heilig@elgi.hu 2. University of L’Aquila, L’Aquila, Italy, massimo.vellante@aquila.infn.it 3. Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland, jreda@igf.edu.pl 4. University of Oulu, Sodankylä, Finland, tero.raita@sgo.fi 5. South African Space Agency Space Science, Hermanus, South Africa, psutcliffe@sansa.org.za Nowcast and forecast of space weather need near real time measurements of the terrestrial plasma environment coupled with models that are able to describe the evolution of the system. PLASMON, a global collaboration of 11 institutions funded by the EU (FP7-SPACE) aims at near real-time monitoring the state of the plasmasphere, and to predict relativistic electron precipitation flux. The near real time monitoring of the plasmasphere is based on continuous ground observations. One pillar is the observation of geomagnetic field line resonances, i.e. eigenresonances of geomagnetic field lines. From the detected resonant frequency the density along the field line can be inferred. Having a meridional chain of magnetometers the monitoring the whole dayside plasmasphere and also the plasmatrough can be realized. These data will be incorporated, together with VLF electron density measurements, into a data assimilative model. To meet the needs of PLASMON, a new European quasi-Meridional Magnetometer Array (EMMA) was established. EMMA is the unification and extension of three pre-existing magnetometer networks (IMAGE, MM100 and SEGMA). Measurements in the Southern hemisphere will be carried out by SANSA in South Africa and Namibia. In the presentation the requirements for the instrumentation making the recorded data suitable for achieving the addressed scientific goals are discussed and the first preliminary results are shown.

64

MAGNETIC VALLEY: A KNOWLEDGE TRANSFER PROJECT

FRANCOIS HUMBLED 1, Jean Rasson 1

1. Institut Royal Météorologique de Belgique, Rue du Centre de Physique B-5670 Viroinval Belgium

We present here how the knowledge transfer project, called “Magnetic Valley”, has grown since it was launched in 2009. This project has been funded by the Belgian government with the purpose to investigate and develop technologies likely to improve socio-economic activity around our Centre de Physique du Globe. First, within our section “Geomagnetic Observations & Instruments”, we further developed the AutoDIF (automatic Diflux) instrument, able to perform automatically absolute measurements of inclination and declination so that AutoDIF is now available to other observatories. Improvements of our facilities and the team members in charge of such outstanding results are presented. AutoDIF measurements are reported separately in these proceedings. Within this section, we also investigate current and potential interest for magnetic declination data or services like compass rose certification, aircraft runway azimuth determination, delivery of isogonal information or maps. The section “Environmental Magnetism" investigates relevance and limitations of magnetic susceptibility measurements in order to map heavy metal pollution in soils. We are currently developing instrumentation and methodology for environmental magnetic methods, and we validate them through comparison with geochemical and other data. One of the scientific interests of section “Ionospheric Sounding” is the understanding of how global navigation satellite systems (GNSS) signals are affected by the ionospheric activity. The latter is controlled, to a large extent, by the geomagnetic activity and disturbances. It has also effects on GNSS-based positioning. We intend to provide specific services tailored to meet the needs of future Galileo users. In addition, we wish also to promote interest for science and engineering among the young public through our educational activities; for instance we offer funding to a local European competition of robotics.

65

WHAT DOES A SURVEY COMPANY NEED FROM GEOMAGNETIC OBSERVATORIES FOR MARINE MAGNETIC SURVEYS?

D. KORYAKIN 1 1. Fugro Gravity and Magnetic Services, Inc., Houston, USA, dkoryakin@fugro.com

Fugro Gravity and Magnetic Services Inc. performs marine gravity and magnetic surveys worldwide. Marine magnetic measurements performed with towed total field magnetometers are greatly affected by geomagnetic field variations that produce erroneous anomalies often indistinguishable from anomalies of geological nature. To account for magnetic variations, the base magnetometer stations are usually established onshore, as close to the survey area, as possible. However, as greatest part of surveys are performed offshore very remote areas of the world, in most cases we use the data from a more remote existing geomagnetic observatory, rather than set up a dedicated base station. Finding an appropriate observatory within a reasonable distance to the survey and sourcing the data from it used to be a challenge. During the last several years, with the growing INTERMAGNET network and many other observatories upgrading towards INTERMAGNET standards, the situation improved significantly. However, marine magnetic survey applications have some specific requirements to magnetic observatory data. For successful correction of magnetic variations we need permanent, non-interrupted total field data recorded 24 hours a day, 7 days a week. The 1-minute sampling proved to be sufficient. The best data format is IAGA-2002, however any fixed field ASCII format containing date, time and total field values, may be used. In most cases preliminary data is sufficient, as a baseline is not important to produce corrections. The main criterion to determine if the observatory data is good for correction of magnetic variations is correlation between observatory and field data. A special decorrelation algorithm has been developed to produce effective correction of magnetic variations. Examples of marine and observatory data, as well as examples of correction are shown in the presentation. Fugro Gravity and Magnetic Surveys, Inc. appreciates the dedicated work of geomagnetic community and believes that close cooperation of a survey company with geomagnetic observatories could be very useful for all sides.

66

A NEW MEASUREMENT METHOD FOR MAGNETIC REPEAT STATIONS

A. LALANNE 1, B. Peltier 2, A. Chulliat 3, D.Telali 4, E. Heumez 5

1. Institut de Physique du Globe de Paris, 1 rue Jussieu, 75238 Paris cedex 05, France, lalanne@ipgp.fr, peltier@ipgp.fr, chulliat@ipgp.fr, telali@ipgp.fr, heumez@ipgp.fr

The French magnetic repeat station network is currently made of 32 stations and has been reoccupied every five years since 1947. During recent surveys, it was found that several stations became unusable due to the increase of nearby human activity. Also, traditional azimuth markers such as church steeples are fragile and easily lost due to new constructions and/or vegetation growth. As a result, it is increasingly difficult to maintain a traditional repeat station network providing accurate measurements over an extended period of time. Another frequently noted limitation of the traditional methodology is the error caused by diurnal variations of ionospheric origin when making measurements during the day. Using a nearby observatory (Chambon-la-Forêt in the case of the French network) to remove these variations is not a satisfactory solution, as the ionospheric field and its induced counterpart may significantly vary over a few hundreds of km. Here we propose a new method for magnetic repeat measurements, where repeat stations are located on airport premises, azimuth sightings are determined using GPS geodetic receivers and magnetic measurements are performed at night (02:00 AM local time) in order to prevent ionospheric field contamination effects. Tests of this method will be reported, as well as initial results of its implementation.

67

PLANS FOR THE CALIBRATION AND SCIENTIFIC VALIDATION OF SWARM INSTRUMENTS AND PRODUCTS

G. OTTAVIANELLI 1, R. Floberghagen 1, G. Plank 2, I. Coco 3, R. Haagmans 2, Y. Menard 2, I. di Lodovico 3

1. ESA / ESRIN, Via Galileo Galilei CP 64 (00044) Frascati (RM), Italy, Giuseppe.Ottavianelli@esa.int 2. ESA / ESTEC, Keplerlaan 1 Postbus 299 (2200) AG Noordwijk, The Netherlands 3. Serco Spa, Via Sciadonna 24 (00044) Frascati (RM), Italy

Swarm is the fifth Earth Explorer mission of ESA’s Living Planet Programme. By using a constellation of 3 identical satellites, the objective of the Swarm mission is to advance the scientific understanding of the Earth’s interior and near-Earth electromagnetic environment and its temporal evolution. For that purpose, high-precision and high-resolution measurements of the strength, direction and variation of the magnetic field will be obtained with the Vector Field Magnetometer (VFM) and the Absolute Scalar Magnetometer (ASM) instruments and complemented by accurate information about the satellites’ orbit and attitude (GPSR and StarTRacker – STR – instruments ). In addition, a tri-axial accelerometer (ACC) and an Electric Field Instrument (EFI, composed by a Langmuir Probe – LP – and a Thermal Ion Imager – TII) will provide the observations required to separate and model the different sources of the geomagnetic field and the near-Earth current systems. Following a brief overview of the current status of the mission including the preparation for launch, the presentation clarifies the plans for the calibration and scientific validation of Swarm instruments and products. It presents the key systems, entities and activities involved in the instrument and data quality monitoring plan. It also describes the activities foreseen during the Commissioning phase and the Exploitation phase, including the key role of the scientific community in this task. The product quality control operational scenarios are also presented, introducing the concepts of the Quality Working Groups.

68

MEXICO MAGNETIC CHART EPOCH 2010.0

G. CIFUENTES-NAVA, Esteban Hernández-Quintero

1. Universidad Nacional Autónoma de México, Instituto de Geofísica, Servicio Magnético, MÉXICO, gercifue@geofisica.unam.mx.

We show a methodology, measurements, and results obtained from campaigns conducted through 2008 to 2012, making a total of 52 repeat magnetic network stations existing in Mexico, for Mexico Magnetic Chart Epoch 2010.0. The last magnetic chart in Mexico was issued in the 90’s by Magnetic Survey of Geophysics Institute-UNAM. We took over the recuperation of lost measurements that had been left over at lack of money and human resources. Practically all the old network was lost or destroyed over of original marks measured in 90’s and it was hard too finding a new good place for replacing these sites. Mostly of the new stations are surrounding 5 km that old ones, located in Schools, Airports, and Sportive Fields. Observed measurements in these sites shown satisfactory records inside the expected rate. MapServer and Google Earth data sources were generated to the final users. The Magnetic Survey was supported through three different sources: IMPULSA5-SIBA Project (Environmental and Biodiversity Informatics System), Extraordinary Near Surface Geophysical Projects, and Teoloyucan Magnetic Observatory Project.

69

SPANISH REPEAT STATION NETWORK IN 2012

JESÚS FERNÁNDEZ 1, Sergio Galán 1, Pablo Covisa 2, Victor Marín 2, Isabel Socias 1 and Jose Manuel Tordesillas 2.

1. Instituto Geográfico Nacional. Madrid. SPAIN. 2. Centro Geofísico de Toledo. Instituto Geográfico Nacional. Toledo. SPAIN. The current Spanish repeat station network consists of 64 stations distributed among Iberian Peninsula, Balearic Islands and Canary Islands. Almost all the stations are measured every two years. A Di-fluxgate sensor mounted on a Zeiss 020B theodolite is used to measure de declination (D) and inclination (I), and a G-856X proton magnetometer to measure the field intensity (F) during D and I observations. There are different kind of repeat stations defined by pillars, platforms and nails fixed with amagnetic concrete. In the poster we can see photographs of them and places used to install the variometer stations. The magnetic components are reduced using variometer stations and the following observatories: San Pablo-Toledo (SPT), Ebro (EBR), San Fernando (SFS) and Güimar-Tenerife (GUI). Also we present the computations and graphs used to reduce the components of the magnetic field (D, H, Z) and a brief study of errors.

70

THE TEAMS OF GEOMAGNETIC OBSERVATORIES IN ARGENTINA.

J.C. GIANIBELLI 1

1. Departamento de Geomagnetismo y Aeronomía, Facultad de Ciencias Astronómicas y Geofisicas, UNLP, Paseo del bosque, 1900 La Plata, Argentina, geofisicogianibelli@yahoo.com.ar

Some of the most important aspects of research projects in Argentina are structure, organization and objectives. Geomagnetism is developed in the National Universities of La Plata, San Juan and in the National Meteorological Service. This paper describes the research projects on Permanent Observatories, objectives, applications, purposes and up to date results. It also presents a historical review of the Permanent Observatories.

71

THE SOUTH ATLANTIC MAGNETIC ANOMALY AND THE NETWORK OF PPM OBSERVATORIES FOR CONTROL

J.C. GIANIBELLI 1, Ricardo Ezequiel García 2, Guillermo Rodríguez 2, Martín Barbosa 2, Nicolas Quaglino 1

1. Departamento de Geomagnetismo y Aeronomía, Facultad de Ciencias Astronómicas y Geofisicas, UNLP, Paseo del bosque, 1900 La Plata, Argentina, geofisicogianibelli@yahoo.com.ar 2. Departamento de Electrónica, Facultad de Ciencias Astronómicas y Geofisicas, UNLP, Paseo del bosque, 1900 La Plata, Argentina, regarcia@fcaglp.unlp.edu.ar One of the most important characteristic features of the geomagnetic field is the South Atlantic Magnetic Anomaly (SAMA). It is characterized by a decrease in the total geomagnetic field intensity and presents the lowest values worldwide. The SAMA minimum values are presented in the northern region of Argentina. For the proposed study presents a network of permanent observatories equipped with digital recording magnetometers every 1 min designed by the Department of Electronics, Faculty of Astronomical and Geophysical Ciences of the UNLP. The location of this instrumental will be in La Quiaca, Tucuman, Cordoba, Bahia Blanca, Comodoro Rivadavia and Rio Grande. The project is supported by the Permenent Network for the Study of the Upper Atmosphere. This paper presents the results of the evolution of the SAMA based on observations of stations and observatories. This activity has the collaboration of the following institutions: the National University of San Juan, Secretary of Geology and Mining of Argentina, National Meteorological Service and CONICET.

72

PLASMON: PROGRESS DURING THE FIRST YEAR

B. HEILIG 1, A. Collier 2, J. Lichtenberger 3, M. Clilverd 4, A. Jorgensen 5, C. J. Rodger 6, M. Vellante 7, R. Friedel 8, R. Holzworth 9, T. Raita 10, J. Reda 11

1. Eötvös L. Geophysical Institute Tihany Geophysical Observatory, Kossuth u. 91, H-8237 Tihany, Hungary, heilig@elgi.hu 2. South African Space Agency Space Science, Hermanus, South Africa, collierab@gmail.com 3. Eötvös university, Budapest, Hungary, lityi@sas.elte.hu 4. British Antarctic Survey, Cambridge, United Kingdom, macl@bas.ac.uk 5. New Mexico Tech, Socorro, New Mexico, United States, anders@nmt.edu 6. University of Otago, Dunedin, New Zealand, crodger@physics.otago.ac.nz 7. University of L’Aquila, L’Aquila, Italy, massimo.vellante@aquila.infn.it 8. Los Alamos National Laboratory, Los Alamos, New Mexico, United States, friedel@lanl.gov 9. University of Washington, Seattle, Washington, United States, bobholz@ess.washington.edu 10. University of Oulu, Sodankylä, Finland, tero.raita@sgo.fi 11. Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland, jreda@igf.edu.pl

Man and equipment in space are affected by the energetic charged particles in the radiation belts. The degree of exposure is determined by the rate of Relativistic Electron Precipitation (REP), which is driven by wave-particle interactions. The properties of the plasmasphere determine the interaction rate. Current models of the plasmasphere do not encompass all of the structure or physics, and observations are sparse. PLASMON will provide regular measurements of plasmaspheric electron and mass densities across all longitudes and incorporate them into a data assimilative model. The observations and model will also be linked to measurements of REP. This poster describes the progress made during the first year of the PLASMON project.

73

MÉXICO 2010.0 GEOMAGNETIC CHART: RESOURCES AND ALTERNATIVES APPLIED TO ANALYZE THE SPACE AND TIME BEHAVIOR OF THE EARTH MAGNETIC FIELD

J. ESTEBAN HERNÁNDEZ-QUINTERO 1, G. Cifuentes-Nava 1 1. Instituto de Geofísica. Univ. Nac. Autónoma de México. estebanh@geofisica.unam.mx.

Between 2009 and 2011 a series of field trips were carried out in order to acquire

geomagnetic data over the area of México. 36 repeat stations were visited and the data

were reduced to 2010.0. Some time-space analysis was presented in the past IAGA-

2008 with older information (now updated). Besides this analysis other criteria was

considered in order to find a better combination among the nowadays resources such as

aeromagnetic surveys, satellite and surface data. As a first approach, the data are

assessed globally and after this a more focused areas were studied. Under the

consideration that certainly exist differences among the type of acquired data (satellite,

airplane, and surface) such as the lack of knowledge of its origin in satellite information,

as well a good cover of the entire planet, or the use of the same kind of magnetometers,

and the distance of the magnetometer from the sources; it may help to recognize time

and space anomalies from every single source. By the other hand, the magnetosphere,

ionosphere and other currents out of Earth may cause the misinterpretation of the main

field measured in the Earth surface; nevertheless looking this combination as an

enhancement of the whole picture; we conclude that after several comparisons, it is

possible to study different aspects of Geomagnetic anomalies in time and space taking

advantage of all consistent data.

74

MONITORIG AND ANALYSIS OF SPATIAL-TIME ALLOCATION OF BAIKAL RIFT ZONE INHOMOGENEITIES Y. LIPKO 1, R. Rakhmatulin 2, S. Khomutov 3 1. Institute of Solar-Terrestrial Physics RAS SB, 126 Lermontov str., Irkutsk, 664033, Russia, lipko@iszf.irk.ru 2. Institute of Solar-Terrestrial Physics RAS SB, 126 Lermontov str., Irkutsk, 664033, Russia, rav@iszf.irk.ru 3. Altay-Sayan Branch of Geophysical Survey of SB RAS, 3 Koptyga str., Novosibirsk, 630090, Russia, khomutov@gs.nsc.ru The results of component magnetic survey in Baikal rift zone (BRZ) including the measurements on Lake Baikal ice between Olkhon and Ushkany Islands in March 2009 (the length of profile more than 150 km) and surface measurements along Tunkinskoy Valley (Sayan, the length of profile is about 170 km) and on Olkhon Island (length of profile is about 90 km) in July 2010 are presented. The precise DI-flux magnetometer 3T2KP were used for observations of magnetic declination and inclination and proton magnetometer POS-1 were used for measurement of total field. The spatial distribution of magnetic field along profiles and the estimate of magnetic element charts are presented. The comparison of the obtained results with historical data for this region and with calculations using reference field model IGRF-11 and NGDC-720 are made. The observations revealed magnetic anomalies in the measurement regions. There are the unique particularities in distribution F along special profiles on Olkhon. There are two strong anomalies of the field with amplitude more than 200 nT. Linear extent both anomaly is about 0.5 km. The observations revealed a large-scale magnetic anomaly in the triangle between the northernmost tip of island Olkhon, cape Ryty, and island B.Ushkany, as well as for Olkhon (magnetic declination D is from -380 arcmin to -320 arcmin, whereas magnetic declination near Irkutsk is about -180 arcmin).Difference between magnetic declinations D in the BRZ region (Olkhon observatory) and Irkutsk since March 2009 to July 2010 was discovered. Decrease of declination at Olkhon observatory is 3 arcmin, while at observatory “Irkutsk’ is 7.5 arcmin. The certain regularities of the spatial distribution component magnetic field are discovered in Tunkinskoy valley. In particular, horizontal component H shows certain reduction trend from Baikal to Mondy (approximately 1000 нТл, from 19800 to 18800 nT).There is significant space variation of the magnetic field in region across Tunkinskoy valleys near observatory Tory. At 6 km distance H-component decreases approximately by 400 nT, D-component increases D by angle of 3 degrees from south edge to north one. The amplitude mode anomalies of irregular pulsation Pi2 under synchronous observations were found in BRZ region. Amplitude of these fluctuations alike at two stations in Tunkinskoy valley (about 50 pT) and has maximum at Olkhon station Uzur (about 150 pT), which is located in BRZ region.

75

MAGNETIC FIELD OBSERVATIONS CLOSE TO THE EPICENTER OF THE 2009 L’AQUILA EARTHQUAKE

F. MASCI 1, M. Di Persio 1, C. Gizzi 1

1. Istituto Nazionale di Geofisica e Vulcanologia, L’Aquila, Italy.

On 6 April 2009 a seismic sequence culminated with the Mw6.3 main shock which hit the town of L’Aquila. The specifics of the L’Aquila earthquakes are that seismic events occurred mainly in the upper crust and that the epicentres were very close to the INGV Geomagnetic Observatory of L’Aquila. These characteristics could justify the observation of possible seismogenic electromagnetic emissions. After April 2009, many papers have retrospectively claimed the observation of pre-seismic electromagnetic signals up to several hundreds of kilometres away from the epicentral area. On the contrary, other studies based on the investigation of magnetic observations coming from the L'Aquila area did not found any electromagnetic precursory signal. Here, we report the analysis of ULF magnetic field data coming from the Geomagnetic Observatory of L’Aquila during the period 2008-2009. Magnetic data are investigated through conventional techniques including the polarization ratio and the fractal analysis. Our study does not show any anomalous signal that could be related with the seismic activity. On the contrary, we show a close correlation of both the geomagnetic field fractal dimension and polarization ratio with the global geomagnetic activity level. In addition, by means of total geomagnetic field observations of the INGV Central Italy tectonomagnetic network, no evident seismogenic pre-earthquake and co-seismic signal has been observed. In conclusion, within the limits of our analyses, the geomagnetic field at L’Aquila Observatory shows a “normal behaviour”, thus no earthquake related signal can be identified.

76

ULF MAGNETIC OBSERVATIONS: AN USEFUL TOOL TO INVESTIGATE THE OCCURRENCE OF EARTHQUAKE PRECURSORS ?

F. MASCI 1

1. Istituto Nazionale di Geofisica e Vulcanologia, L’Aquila, Italy.

For almost thirty years, many researchers have investigated ULF magnetic data in the hope of finding possible pre-earthquake seismogenic signals. Several ULF stations have been installed for this purpose and many papers have claimed the observations of pre-earthquake ULF signatures. These claims motivate the belief that short-term earthquake prediction based on magnetic data may one day become a routine technique. Since the earthquake prediction is a very important topic of social importance, some researchers have recently investigated the authenticity of the ULF earthquake precursors. These studies show that the previous claimed seismogenic signatures were actually part of normal geomagnetic activity caused by the solar-terrestrial interaction. Here, the results of these reviews are discussed in the hope of shedding light on the usefulness of the ULF magnetic measurements to study the occurrence of pre-earthquake seismogenic signals.

77

TIME EVOLUTION OF MAGNETIC NOISE OVER THE PAST YEARS AT L'AQUILA GEOMAGNETIC OBSERVATORY

P.PALANGIO,C. Di Lorenzo, M.Pietrolungo, L.Santarelli

1. Istituto Nazionale di Geofisica e Vulcanologia, Castello Cinquecentesco, 67100 L'Aquila, Italy. paolo.palangio@ingv.it.

We conducted a statistical study of the background magnetic noise level in the frequency band from 1 mHz to 0.5 Hz, selecting the quietest geomagnetic periods during the last three years. The total noise level includes the natural noise floor as well as antropogenic noise generated by vehicles and trains. It is difficult to discriminate the man-made noise from the residual natural noisy variation of the geomagnetic field still present on the quietest geomagnetic days with Kp=0. Our analysis is based on differential measurements between the two permanent observatories of L'Aquila and Duronia. Despite of increased level of urbanization in the area around the observatory after the April 6, 2009, Mw 6.3 L'Aquila earthquake, we observe an atypical magnetic noise reduction after the earthquake in the ULF band.

78

SECULAR VARIATION OF GEOMAGNETIC FIELD AT THE INDIAN EQUATORIAL STATION, TIRUNELVELI (TIR)

E. PARAMASIVAN 1, Sheikbareeth. P 1, Sathishkumar.S 1 and Pathan. B.M 2.

1. Equatorial Geophysical Research Lab, Indian Institute of Geomagnetism,Tirunelveli-627011, India, elango.iig@gmail.com.

2. Indian Institute of Geomagnetism, Navi Mumbai-410218, India, bmpathan@iigs.iigm.res.in.

IGRF ( International Geomagnetic Reference Field) yearly mean data for a period of 115 years, i.e. from 1900 to 2015 were used to understand the secular variation of geomagnetic field at Equatorial Station Tirunelveli (Geog. Lat. 8.7 N; Long. 77.8 E) (Geom. Lat. 0.03, Long. 150.4). Observational values available for 15 years from 1996 to 2011 are also analyzed and compared with IGRF model values. Total field ‘ F ’ shows a continuous increasing trend for a period of 50 years, then a slight downward trend for 40 years and a continuous and sharp increase thereafter. Inclination ‘ I ’ shows a typical variation between 1900 and 1970, which clearly indicates the southward(1900-1925) and northward movement (1925–1970) of Dip equator. Later a continuous and rapid increase in inclination reveals the further southward movement of dip equator. The steady increase of vertical component (Z) substantiates the southward movement of dip equator and the trend is in good agreement with the IGRF model. Results from this analysis will be discussed in detail.

79

A NEW EUROPEAN GROUND MAGNETIC OBSERVATION NETWORK IN THE FRAME OF THE PLASMON PROJECT

J. REDA 1, B. Heilig 2, M. Neska 1, M. Vellante 3

1. Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland, jreda@igf.edu.pl, nemar@igf.edu.pl 2. Tihany Geophysical Observatory, Eotvos Lorand Geophysical Institute, Tihany, Hungary, heilig@elgi.hu 3. Physics Department, University of L’Aquila, L’Aquila, Italy, massimo.vellante@aquila.infn.it

Currently, there is being built up a quasi meridian-along network of ground magnetic stations including sites in seven countries between North Scandinavia and the Apennine Peninsula. We want to present this network that was developed in the frame of the PLASMON project funded by the European Union (FP7-SPACE). Its purpose is to complete present magnetometer measurements performed in observatories and in other places in order to investigate the magnetosphere. Continuous recording of magnetic pulsations in the ULF band, real-time access, and immediate tracing of the Field Line Resonance (FLR) phenomenon shall enable us to carry out a real-time monitoring of the state of the plasmosphere.

80

SAMOA GEOMAGNETIC OBSERVATIONS; PAST, PRESENT AND FUTURE A. ME SALE 1, B. SiosinameleLui 1 1. Ministry of Natural Resources and Environment, Division of Meteorology, Geophysics Section, Samoa, faigame.sale@mnre.gov.ws, siosina.lui@mnre.gov.ws The Apia Geomagnetic Programme (AGP) was originally set up by the Germans in 1902 in an expedition to explore the Antarctic. It was later continued by New Zealand (GNS) after the First World War until it was taken over by the Samoan government when it gained independence in 1962. It is one of the longest operational stations in the Southern hemisphere and one of great importance to the international scientific community. Although the AGP is a participant member of Intermagnet, much of the data processing was conducted by the late Lester Tomlinson of (Geoserve New Zealand), who was highly involved in the initial establishment of the AGP while serving as an employee of DSIR (now known as GNS New Zealand) and later by Tony Hurst of GNS, Jeffrey Love and Alan Berarducci of USGS. GNS New Zealand, have been part of the AGP for many years, and have provided much of the technical support required by the program in terms of equipment assistance as well as an informal representative of the AGP to the international community. This in a way, has created a large level of dependency within the AGP with respect to sustaining the programme, clearly, this is an issue that needs to be addressed. The current economic instability facing the world today has also affected the AGP in Samoa, the AGP is not considered a priority program for the development of Samoa and this has had a major effect on the program as it has been affected by budget cuts, training and scholarship opportunities. Despite the importance of the program to the international scientific community, to date Samoa still does not have a qualified Geomagnetic Scientist; clearly, this is something that the program needs collaboration with the international community and the government of Samoa to ensure that the program continues and strengthened in years to come.

81

DIURNAL PRECESSION OF THE POLE OF THE EFFECTIVE MAGNETOSPHERIC CURRENTS ACCORDING TO THE GEOMAGNETIC OBSERVATORY DATA

V.Yu. Semenov 1, J. Vozar 2,3, Y. P. SUMARUK 4

1. Institute of Geophysics, Polish Academy of Sciences, Ks. Janusza 64, Warsaw, Poland;

sem@igf.edu.pl. 2. Geophysical Institute, Slovak Academy of Science, Bratislava, Slovakia;

geofvozar@savba.sk. 3. Dublin Institute for Advanced Studies, Dublin, Ireland; vozar@cp.dias.ie. 4. Institute of Geophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine;

sumar@mail.lviv.ua

It is believed that configuration of magnetospheric effective currents at a distance 4-5 Earth’s radii is held in position by the geomagnetic field. The geomagnetic field is the main dipole part of the Earth’s magnetic field. It can be computed only, i.e. it cannot be directly observed as such on the Earth. Both these fields are moving relatively to each other with acceleration during the last century. The velocity of the magnetic pole is now reached ≈ 50 km/year while the velocity of the geomagnetic pole is much less. So a disparity between positions of both poles is currently changing. This process obviously affects the currents in the ionosphere and magnetosphere of the Earth which are the main sources of the fields for deep sounding of the Earth’s mantle. However the position of the geomagnetic pole can be fixed using the magnetic storms which fields are linearly polarized. The directions of the field polarization at several observatories separated along longitude allow fixing positions of the pole connected with the magnetospheric ring currents. Diurnal precessions of this pole around the geomagnetic one have been detected using hourly data of several geomagnetic observatories in the Eurasia.

82

GEOMAGNETIC OBSERVATION NETWORK IN THE EAST OF RUSSIA

BORIS SHEVTSOV 1, Sergey Khomutov 1, Stanislav Nechaev 2, Igor Poddelskiy 3, Mikhail Basalaev 4, Zinaida Dumbrava 5, Ilkhambek Babakhanov 6, Sergey Smirnov 7, Nina Cherneva 8.

1. IKIR FEB RAS, Russia, hom@ngs.ru 2. IKIR FEB RAS, Russia, sen@irlan.ru 3. IKIR FEB RAS, Russia, magadangfo@gmail.com 4. IKIR FEB RAS, Russia, basalaevmaikl@mail.ru 5. IKIR FEB RAS, Russia, labfiz@vzm.kht.ru 6. IKIR FEB RAS, Russia, ilham@ikir.ru 7. IKIR FEB RAS, Russia, sergey@ikir.ru 8. IKIR FEB RAS, Russia, nina@ikir.ru

The results of development of geomagnetic observation network in the Far-East of Russia are presented; the system includes six observation sites: Cape Shmidt(CPS), Magadan(MGD), Paratunka(PET), Khabarovsk(KHB), Sakhalin, Ussuriysk. This year the stations are being equipped with modern GSM19FD Magnetometers, operating on the basis of Overhauser effect, constructed by GEM Systems Company, Canada. After installation of the magnetometers, they will work in test regime for about a year. Observation data will be sent to an information center in IKIR FEB RAS, Kamchatka. At Magadan and Paratunka observatories modern magnetometers for variation and absolute observations are installed according to the agreement between IKIR FEB RAS and GeoForschungsZentrum Potsdam (GFZ), Potsdam, Germany. These observatories are the participants of Itermagnet international project. Khabarovsk observatory is also planned to be a part of it. At Cape Shmidt, Magadan and Paratunka observatories variometers of MAGDAS system are installed. Cooperation on this project is realized with Space Environment Research Center of Kyushu University, Japan. At Magadan and Paratunka observatories FRG variometers are installed. Such variometers are planned to be installed at Cape Shmidt. These observations are carried out within the framework of cosmic weather research program together with National Institute of Communication Technology, Japan.

83

DEAD SEA SINKHOLES DETECTION USING MAGNETIC METHOD

B. SHIRMAN 1, M. Rybakov 2

1. Survey of Israel, 1, Lincoln St., Tel-Aviv 65220 Israel, bshirman@gmail.com 2. The Geophysical Institute of Israel, P.O.B. 182, Lod 71100, Israel, rybakovmichael6@gmail.com

Sinkholes are a serious hazard in the Dead Sea area. They started appearing in the area in the last two decades due to the dramatic drop in the Dead Sea’s water level soon became a major problem for commercial and industrial development. Sites with large, open sinkholes and collapse features have been identified throughout a wide region. Several geophysical methods have been employed to investigate and predict the occurrences; these include seismic, geoelectric, EM, microgravity. To test the capability of the magnetic method we studied the magnetic properties of the geologic sequence in situ along the western Dead Sea shore. Numerous measurements of magnetic susceptibility were carried out outside and inside of the open sinkholes. The value was in the range of 16-40 micro-CGS. Preliminary 3D modeling suggested that voids, similar in volume to the known sinkholes, caused measurable magnetic anomalies of a few nT. Magnetic surveys were conducted at some sites with different geologic settings (i.e. alluvial fans, mud flats). The sinkholes were recognizable in the data. Hence, the magnetic method appears to be an efficient method for predicting the sinkholes.

84

THE TOTAL FIELD CHANGE BEFORE THE YUSHU EARTHQUAKE AND ITS AFTERSHOCKS

Dongmei Yang1, YUFEI HE1, Suqin Zhang1

1 Institute of Geophysics, China Earthquake Administration, Beijing, 100081, China, ydmgeomag@263.net

Since the year of 2008, there have been continuous recording of total field at about one hundred magnetic stations in China. The instruments for the recording are Chinese proton magnetometers with one sample/min and Canadian Overhauser magnetometers with 1Hz sampling. In order to find the crustal field change before earthquakes, we calculated the daily mid-night values for total field at all the stations from the year of 2008 to the year of 2011 and then the daily rate of the mid-night values. We studied the spatial distribution of the rate and found some strange changes in the northward area of the epicenters three months before the mainshock of the Ms7.1 Yushu Earthquake and a few days before the aftershocks.

85

Session V Data Processing and

Management

 

87

IMPROVING OLD MAGNETIC DATA PRODUCT BY USING COMPREHENSIVE MODELS M. CATALÁN 1, M. LARRÁN 1, N. FERNÁNDEZ 1 1. Royal Observatory of the Spanish Navy, San Fernando, Spain, mcatalan@roa.es Magnetic observatories have been in charge of recording variation of the earth’s magnetic field. historically old data allow us to delineate its long term components only, while nowadays we are able to fill an almost continuous recording. Sometimes previous to the settlement of a magnetic observatory, only isolate absolute magnetic measurements are available. they have been useful to work out global models or to track its secular variation but with a high degree of uncertainty. Other situations show observatories where due to technical problems or interferences have never been possible to track one of the different components of the geomagnetic vector, while absolute observations did exists. During past decade several comprehensive models (cm3 and cm4 later) were developed where data from magnetic field satellites pogo, magsat, ørsted, and champ, and from magnetic observatories from the early 1960s to 2002 were incorporated. they were able to estimate the external fields contribution by using algorithms were sun f107 and dst indexes were needed. it makes possible to extend its application out of the period where they were initially designed, only conditioned to the existence of f107 and dst parameters. in this presentation we will consider the use of its external fields estimation facility to improve our secular magnetic record’s knowledge showing different situations and observatories records.

88

TRANSMISSION OF MEASURING DATA FROM GEOMAGNETIC OBSERVATORY SINJI VRH (SLOVENIA) IN CONSTRUCTION

Rudi Čop 1, DAMIR DEŽELJIN 1

Higher Education Centre Sežana, Laboratory for Geomagnetism and Aeronomy, Kraška ulica 2, 6210 Sežana, Slovenia.

During the testing of the operation of the Geomagnetic Observatory Sinji Vrh, most time was dedicated to the magnetometers; and next to the remote collecting of the measuring data and their graphical presentation in near real time. The telemetry development was based on the practical experiences gained during the work on the existing international information systems for observing the physical parameters measured on site in our country. The observation of the change in the geomagnetic field at the Observatory, which was made possible by the telemetry, enabled a step-by-step discovery of the sources that caused such changes and an improvement in both the measuring system and telemetry. For the purpose of continuous monitoring and quality control of the measured data and the improvement of operation reliability, a parallel measuring system and telemetry as well as the storage of the measuring data on two separate servers are being developed. During the process of data acquisition the measured data are disassembled and stored in a structured form. Next, the data are transmitted to the central server, where the data are passed through a basic consistency check and stored in a relationship database. Afterwards the stored data are post processed.

89

DEVELOPMENT OF QUASI-DEFINITIVE AND ADJUSTED MAGNETIC OBSERVATORY DATA AT THE US GEOLOGICAL SURVEY

A. FINN, CAROL A. 1, B. E. William Worthington, 1, C. Eddie McWhirter, 1, Jill E. Caldwell, 1

1. U.S. Geological Survey, Denver, CO, USA, cafinn@usgs.gov, bworth@usgs.gov, emcwhirter@usgs.gov, jcaldwell@usgs.gov During the past two years, the US Geological Survey (USGS) has implemented new data processing steps to produce quasi-definitive data and adjusted data for selected USGS magnetic observatories. Quasi-Definitive data is produced on a monthly basis, usually mid-month. The raw data are cleaned of obvious noise spikes and adjusted using up-to-date verified baseline data. Quasi-Definitive data are currently produced for 4 USGS observatories (BOU, CMO, FRD, and HON) and are available from the prototype INTERMAGNET data download and USGS geomagnetic display and download websites. Adjusted data are produced by applying a least-squares linear fit to the preceding 4 to 8 weeks of baseline data and projecting it forward to apply a provisional baseline correction to the raw data in real-time. The adjusted data are compared with absolute measurements to check their accuracy. Results have shown that, when regular absolutes are taken, the adjusted data values are within +/- 5 nT of the absolute values. Adjusted data are now produced at 4 observatories (BOU, BRW, DED, and FRD) and will eventually be implemented at all observatories. The data will be available on the USGS web site by the end of 2012. These improved data products are useful for applications such as calculation of geomagnetic activity indices in near real-time and for geomagnetic field modeling.

90

MAGPY – A PYTHON BASED SOFTWARE FOR ANALYZING GEOMAGNETIC OBSERVATORY MEASUREMENTS

ROMAN LEONHARDT 1, Jürgen Matzka 2

1. Conrad Observatory, Central Institute for Meteorology and Geodynamics, Vienna, Austria 2. National Space Institute (DTU Space), Technical University of Denmark, Copenhagen, Denmark

The PyMag software is a platform independent, multi-purpose software to assist geomagnetic data analysis primarily in observatory environments. It supports various common data formats of the geomagnetic community, among them instrument specific formats and general purpose formats like IAGA02, cdf and hdf5. Direct url-data access is also possible and new format conventions can be easily incorporated. Using the scriptable access of the underlying functions for import, treatment, and export of data, an automated real-time analysis of geomagnetic data is possible. Currently supported are variometer data, scalar data and absolute measurements. For this, basic analysis features like filtering (gaussian, linear), smoothing and data fitting routines are available. Baseline stability tests, outlier detection and flagging procedures allow for a detailed examination of data quality. The package is completed by routines for coherence and spectral analysis as well as k-index calculation and variation (storm) detection making use of well established routines from the seismological community. Beside the scriptable access and command line routines, a graphical user interface based on Python WX is provided which allows, platform independent, windowed access to most routines and a direct graphical demonstration. The software has currently been tested on Linux and Windows systems.

91

OBSERVATORY DATA QUALITY CHECK – THE INSTRUMENT TO ENSURE VALUABLE RESEARCH

H.-J. LINTHE 1, J. Reda 2, A. Isac 3, J. Matzka 4, C. Turbitt 5

1 GFZ Potsdam - Adolf Schmidt Geomagnetic Observatory, Lindenstr. 7 14823 Niemegk Germany, linthe@gfz-potsdam.de

2 Institute of Geophysics Warsaw - Central Geophysical Observatory 05-622 Belsk, Poland, jreda@igf.edu.pl

3 Geological Institute of Romania, No. 1 Caransebes Str. Sector 1 Bucharest RO-012271, Romania, margoisac@yahoo.com

4 Technical University of Denmark - National Space Institute, Juliane Maries vej 30 Building Rockefeller 2100 Copenhagen, Denmark, jrgm@space.dtu.dk

5 British Geological Survey, West Mains Road Edinburgh EH93LA, United Kingdom, cwtu@bgs.ac.uk

Observatory data are the basement for the international scientific research. Valuable results can be achieved only if the data are precise and faultless. High quality instruments and high level ability and motivation of the observatory personnel are necessary. But as important are data quality checks. Observatory data are useful for the science only if they are carefully checked before their publication. INTERMAGNET encourages the observatories (IMOs) to check their definitive data before they are submitted. Further more the definitive data are carefully double-checked by the Definitive Data Subcommittee before they are made available for the use. This procedure ensures a high security of data quality. Different methods of data checks are presented. Their efficiency is discussed considering the different instrumental base of the observatories. Insights and motivation will be given for the necessity of data checks. The tools for effective data checks are presented.

92

CURRENT HARDWARE AND SOFTWARE DEVELOPMENT FOR THE USGS

T. WHITE 1

1.oUS Geological Survey, Geomagnetism Group

The USGS has engaged in the development of a new data collection system. The new system will be based upon a field-programmable gate array (FPGA) platform. This will increase reliability when compared to the current Windows operating system (OS) based acquisition system. The FPGA system will have upgraded data collection characteristics, including higher sampling rates, simultaneous sampling of all three Narod magnetometer axes, and increased voltage input range. USGS has also begun development on web-based display software, web-based absolutes entry and processing software, and new definitive data processing software. Moving to web-based programming removes the dependency on a specificOS, and provides immunity from OS updates. The new data processing software will be designed to produce higher frequency data products, as well as address the increasing need for intermediate data products such as Quasi-definitive data.

93

K INDICES STATISTICAL VARIATIONS: BETWEEN MINUTE AND SECOND DATA

A. CHAMBODUT 1, M. Menvielle 2,3

1. EOST, Dep. of Magnetic Observatories; IPGS, CNRS-INSU UMR 7516, Strasbourg, France, aude@unistra.fr 2. Université de Versailles St-Quentin; LATMOS-IPSL, CNRS-INSU UMR 8190, Guyancourt, France, michel.menvielle@latmos.ipsl.fr 3. Université de Paris-Sud, Département des Sciences de la Terre, Orsay, France. INTERMAGNET observatories have undertaken the production of second data. This effort was motivated to allow studies of rapid variations of external origin at higher frequencies. This change in the sampling interval may impact the calculation of K indices at each observatory location. In this study, 2-second and 1-minute historical data of magnetic observatories are used to assess the impact of sampling interval as a function of Local Time, seasons and latitude. This study aims at providing a quantitative basis for deciding whether K indices have to be calculated as accurately as possible (from second data) to allow a better definition of K derived geomagnetic indices, or to be defined from only minutes data in order to keep the homogeneity of series.

94

ACCURACY OF ONE-HOUR MEANS OF GEOMAGNETIC ELEMENT H HAVING MISSING DATA

P. Dolinský1, F. VALACH1, M. Váczyová1

1. Geomagnetic Observatory, Geophysical Institute, Slovak Academy of Sciences, Hurbanovo, Slovak Republic, geomag@geomag.sk

This study deals with production of one-hour geomagnetic elements data from incomplete one-minute data sets. We solved this problem analytically, employing some statistical properties of the data file used. The statistical properties were derived from the one-minute data of the horizontal component (H) of the geomagnetic field registered by the mid-latitude magnetic observatory Hurbanovo (HRB) in years 1997 to 2009. That means that roughly one complete cycle of the solar activity was covered with the data. Statistical properties of the subsets containing one-minute data within one-hour periods were determined with regard to subset averages as well as to the regression lines. We assigned quantitatively the number of data in the statistical sample which is required in order to achieve the predetermined value of accuracy (σ = 1 nT) as function of the slope of the regression line. Significant effect of the geomagnetic diurnal variation to the results of the analysis emerged. This fact strikes against the commonly used recommendations about missing data based on geomagnetic indices (Dst, Kp etc.), which are rid of the diurnal variation. In order to make certain of it, we performed a separate analyses for three categories of the geomagnetic activity, respectively for Dst > -100 nT, Dst between -100 nT and -200 nT, and Dst < -200 nT.

95

A STATISCAL STUDY OF LT VARIATIONS OF aλ SECTORIAL GEOMAGNETIC ACTIVITY INDICES

F. El-Lemdani Mazouz 1, M. MENVIELLE 1,2, A. Chambodut 3, A. Marchaudon 4, C. Lathuillière 5 1. Université de Versailles St-Quentin; LATMOS-IPSL, CNRS-INSU UMR 8190, Guyancourt, France, michel.menvielle@latmos.ipsl.fr 2. Université de Paris-Sud, Département des Sciences de la Terre, Orsay, France 3. EOST, Dep. of Magnetic Observatories; IPGS, CNRS-INSU UMR 7516, Strasbourg, France, aude@unistra.fr 4. Université d'Orléans; LPC2E, CNRS-INSU UMR 7328, Orléans, France 5. Université Joseph Fourier - Grenoble 1; IPAG, CNRS-INSU UMR 5274, Grenoble, France Solar-wind/magnetosphere interactions are not symetric and show a local time dependency. In order to better describe this effect, we use aλ longitude sector geomagnetic activity indices. These indices are calculated thanks to am network observatories and thus reflect the geomagnetic activity at sub-auroral latitudes. In this study, we present a statistical study of the variations of the aλ sectorial activity indices as a function of local time and seasons.

96

OVERVIEW OF THE STABILITY OF BASELINE VALUES FOR 1-SEC FLUXGATE MAGNETOMETER LEMI-025 AT HERMANUS OBSERVATORY

E. NAHAYO 1, P. B. Kotzé 2, E. Julies 3

1. South African National Space Agency (SANSA) Space Science, PO Box 32, Hermanus, South Africa, enahayo@sansa.org.za 2. South African National Space Agency (SANSA) Space Science, PO Box 32, Hermanus, South Africa, pkotze@sansa.org.za 3. South African National Space Agency (SANSA) Space Science, PO Box 32, Hermanus, South Africa, ejulies@sansa.org.za

SANSA Space Science operates 4 permanent observatories which are INTERMAGNET members (Hermanus, Hartebeesthoek, Tsumeb and Keetmanshoop). The FGE fluxgate magnetometer is the only vector magnetometer running at these observatories and records data at a sampling rate of 5-sec from which 1-min data is obtained. In the future, one of the requirements from these observatories is to submit real-time 1-second data to their GIN (Geomagnetic Information Node). 1-second Fluxgate Magnetometer LEMI-025 was recently installed at Hermanus to investigate the stability of baseline values and have a hands-on experince for its succesful installation at other observatories in the near future. The investigation of the stability of baseline values was conducted and the baseline values of the LEMI-025 and FGE fluxgate magnetomers were compared. The results show that the baseline values of 1-second Fluxgate magnetometer LEMI-025 are stable at Hermanus observatory.

97

WP INDEX: A NEW SUBSTORM INDEX DERIVED FROM HIGH-RESOLUTION GEOMAGNETIC FIELD DATA AT LOW LATITUDE

M. NOSÉ 1, T. Iyemori 1, L. Wang 2, A. Hitchman 2, J. Matzka 3, M. Feller 4, S. Egdorf 4, S. Gilder 4, N. Kumasaka 5, K. Koga 6, H. Matsumoto 6, H. Koshiishi 6, G. Cifuentes-Nava 7, J. J. Curto 8, A. Segarra 8, C. Celik 9

1 Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University, Kyoto, Japan, nose@kugi.kyoto-u.ac.jp.

2 Geoscience Australia, Canberra, Australia. 3 DTU Space, National Space Institute, Technical University of Denmark,

Copenhagen,Denmark. 4 Geophysical Observatory Fürstenfeldbruck, Department of Earth and Environmental

Sciences, Lud-wig Maximilians Universität, Munich, Germany. 5 Kakioka Magnetic Observatory, Japan Meteorological Agency, Ibaraki, Japan. 6 Aerospace Research and Development Directorate, Japan Aerospace Exploration

Agency, Ibaraki, Japan. 7 Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico City,

Mexico. 8 Observatori de l’Ebre, CSIC - Universitat Ramon Llull, Horta Alta, Spain. 9 Kandilli Observatory and Earthquake Research Institute, Boğzici University,

Istanbul, Turkey.

Geomagnetic field data with high time resolution (typically 1 s) have recently become more commonly acquired by ground stations. Such high time resolution data enable identifying Pi2 pulsations which have periods of 40-150 s and irregular (damped) waveforms. It is well-known that pulsations of this type are clearly observed at mid- and low-latitude ground stations on the nightside at substorm onset. Therefore, with 1-s data from multiple stations distributed in longitude around the Earth’s circumference, substorm onset can be regularly monitored. In the present study we propose a new substorm index, the Wp index (Wave and planetary), which reflects Pi2 wave power at low-latitude, using geomagnetic field data from 11 ground stations (Tucson, Honolulu, Canberra, Kakioka, Learmonth, Urumqi, Iznik, Fürstenfeldbruck, Ebro, Tristan da Cunha, and San Juan). We compare the Wp index with the AE and ASY indices as well as the electron flux and magnetic field data at geosynchronous altitudes for 11 March 2010. We find that significant enhancements of the Wp index mostly coincide with those of the other data. Thus the Wp index can be considered a good indicator of substorm onset. The Wp index, other geomagnetic indices, and geosynchronous satellite data are plotted in a stack for quick and easy search of substorm onset. The stack plots and digital data of the Wp index are available at the web site (http://s-cubed.info) for public use.

98

AN INSTRUMENT PERFORMANCE AND DATA QUALITY STANDARD FOR INTERMAGNET ONE-SECOND DATA EXCHANGE

C. TURBITT 1, J. Matzka 2, J. Rasson 3, B. St-Louis 4, D. Stewart 5

1. British Geological Survey, West Mains Rd., Edinburgh, EH9 3LA, U. K., cwtu@bgs.ac.uk.

2. DTU Space, Juliane Maries vej 30, 2100 København, Denmark, jrgm@space.dtu.dk 3. Institut Royal Météorologique, Centre de Physique du Globe, B-5670 Dourbes,

Belgium, jr@oma.be 4. Natural Resources Canada, Geomagnetic Laboratory, 7 Observatory Crescent,

Ottawa, Ontario, Canada, K1A 0Y3, stlouis@geolab.nrcan.gc.ca 5. USGS Golden, Box 25046, MS966, DFC, Denver CO 80225, USA,

dcstewart@usgs.gov

With the advent of developments in instrumentation, data acquisition and data dissemination, an increasing number of observatories are producing a filtered one-second data product in addition to traditional one-minute data, hourly means, daily means, monthly means and annual means. An INTERMAGNET survey of the user community in 2005 concluded that there is a desire for one-second data to be made available through the INTERMAGNET network and that, as is the case for one-minute data, a minimum standard of instrument performance and data quality should be set for definitive one-second data. Here, the INTERMAGNET Observatories & Standards Subcommittee introduces such a one-second data standard resulting from consultation with the scientific community and instrument developers.

99

THE CHARACTERISTIC OF THE NEW GEOMAGNETIC ACTIVITY INDEX VR

Xiuyi Yao1, Dongmei Yang1, YUFEI HE1, Yahong Yuan1

1 Institute of Geophysics, China Earthquake Administration, Beijing, 100081, China, xyuan23@yahoo.com.cn

Vr which represent the variation rate of the geomagnetic field is a new geomagnetic activity index. It was obtained by calculating the hourly standard deviation of the first differences of the geomagnetic horizontal component minute data. Based on the comparison between Vr and Kp and between Vr and ap, it is found that generally Vr changes linearly with Kp and ap which means that usually rapid changes exist together with the disturbances. But there are exceptions. So Vr is an index that can be used to detect geomagnetic disturbances from the magnetosphere and is more sensitive to the variation rate of the geomagnetic field rather than the field itself. Here, we focuses on analyzing of the characteristics of the Vr index, and tend to find out the its physical source, which can lay the basis for applying the Vr index in monitoring of geomagnetic activity.

100

Session VI Applications

 

102

A STUDY OF PHASE CHARACTERISTICS OF GEOMAGNETIC JERKS USING COMPLEX WAVELETS

E. CHANDRASEKHAR, P. Prasad 1

1.oDepartment of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai-76, India, e-mail: esekhar@iitb.ac.in

Complex wavelet analysis was performed on the geomagnetic east-west component data of about 75 years, recorded at 81 global magnetic observatories to understand the phase characteristics of well reported global as well as local Geomagnetic Jerks (GJs) together with their space-time and time-frequency localization. Phase information provides clues about the direction of the convective outer core motions, responsible for occurrence of jerks. Around the time of occurrence of GJs, the phase changes in the secular variation data are manifested by convex shape (slope changing from negative to positive) or concave shape (slope changing from positive to negative). Based on their phase content, we have made a systematic study of the well reported global GJs and some local GJs by segregating the observatory data into polar regions, high-latitude to mid-latitude regions, mid-latitude to equatorial regions and southern hemisphere regions. By testing different complex wavelets, we have identified Cgau1 wavelet as the ideal one to understand the phase characteristics of GJs. We discuss the interpretation of results in the light of the hemispherical differences observed in the occurrences of GJs.

103

GEOMAGNETIC SECULAR ACCELERATION ANALYSIS FROM MAGNETIC OBSERVATORY DATA

A. CHULLIAT 1

1. Institut de Physique du Globe de Paris, 1 rue Jussieu, 75238 Paris cedex 05, France, chulliat@ipgp.fr

Recent geomagnetic field models such as CHAOS-4 and GRIMM-2 have shown that it is now possible to investigate the time variability of the geomagnetic secular acceleration, i.e., the second derivative of the main magnetic field. In a recent study (Chulliat et al., GRL, 2010), a secular acceleration “pulse” was identified in the CHAOS model, reaching its maximum power around 2006 at the core surface. The pulse was found to be most intense under the Equatorial Atlantic Ocean and the Eastern Indian Ocean. Before (around 2003) and after (around 2007) the pulse, geomagnetic jerks were detected in observatory data. Here I extend this analysis by directly modeling the secular acceleration over the 2000-2012 time interval from observatory data, including quasi-definitive data for the most recent part of the interval. To this aim, unconventional monthly means are calculated from hourly mean values, after removing the part of the signal attributed to external fields. Based of the analysis results, an assessment of the robustness of the 2006 pulse is provided and possible mechanisms leading to the formation of the pulse are discussed.

104

A METHODOLOGY TO DETECT CALM DAYS

J. C. GIANIBELLI 1, Nicolas Quaglino 1

1. Departamento de Geomagnetismo y Aeronomía, Facultad de Ciencias Astronómicas y Geofisicas, UNLP, Paseo del bosque, 1900 La Plata, Argentina, geofisicogianibelli@yahoo.com.ar

One of the important elements to detect the geomagnetic activity is the total intensity of geomagnetic field F. In this paper we presents the design of an activity index that allows for different scales of time in comparison with classical indexes to determine which days are quiet (Q days). The results are presented for the observatories of Trelew, Las Acacias, Vassouras, Kourou and Huancayo. It is concludes that it is possible to detect the low levels of activity of calm days for each observatory individually and extend the metodology to all magnetic observatories of the world.

105

A NEW METHOD TO REDUCE THE DAILY VARIATION NOISE FROM GEOMAGNETIC OBSERVATORY

S. POURBEYRANVAND 1

1. Institution of Geophysics, North Kargar St., Amir Abad, Tehran, Iran shpour@ut.sc.ir

In this study we propose a new method to reduce the daily variation noise from geomagnetic observatory data. This will be helpful to identify the weak signals in the geomagnetic records, possibly related to the earthquake occurrence as an example. The method is based on plotting different components of the magnetic field in specific time intervals in a 24 hours frame. This study shows that this kind of plotting of the records will reveal the nature of the daily variation of the geomagnetic filed in the site called the characteristic curve. Thus the behavior of the geomagnetic field components in the station can be predicted approximately. Therefore the measurement values will be adjusted with respect to the expected values, avoiding the environmental noise as much as possible. The method has been tested successfully using the geomagnetic observatory data, obtained from SPIDR (space physics interactive data source) and the correlation of geomagnetic anomalies in the observatory record and one earthquake in India is investigated. This correlation is shown to be improved after applying the proposed processing approach.

106

TIPPERS AT COSTAL AND ISLAND GEOMAGNETIC OBSERVATORIES. A USEFUL TOOL TO PROBE ELECTRICAL CONDUCTIVITY OF THE EARTH’S CRUST

F. SAMROCK 1, A. Kuvshinov 1

1. Institute of Geophysics, ETH Zürich, Switzerland For decades time series of hourly mean values of three geomagnetic field components measured on a global net of observatories have been routinely used to recover mantle electrical conductivity. Bearing in mind one hour sampling rate, and depending on the period, two global sources are used for these studies: (1) daily variations with periods between 4 and 24 hours, caused by electric currents flowing in the ionosphere; (2) irregular (Dst) variations with periods longer than one day, caused by modulation of ring current flowing in the magnetosphere. These variations provide information about conductivities at depths between 300 and 2000 km. Nowadays most observatories provide the data in a form of minute means which allows for analysis of the geomagnetic variations at periods between a few minutes and a few hours. There is a common consensus that these variations are generated by auroral ionospheric current system which is seen at mid-latitude observatories as vertically propagated plane wave of time-varying polarization. These variations can, in principle, provide information about geoelectric structures at crustal depths (< 300 km). However, for the best of our knowledge there were no attempts to use these data to infer the conductivity of the Earth’s crust. The reason seems to be rather intuitive and looks as follows. For a given, isolated observatory (and for the considered period range) one can at best to determine 1-D local conductivity structure beneath the observation site. Assuming plane wave excitation, the only response function which might be then constructed is the so-called tipper which connects vertical magnetic component with two horizontal components. But the tipper is zero for 1-D conductivity models, due to vanishing vertical component. This line of reasoning advocates ignoring these data to probe the Earth’s crust in the frame of 1-D models. This is probably true for inland observatories, but it is not for the coastal and island sites. In this work we demonstrate that tippers at coastal and island observatories - being large due to ocean effect - are sensitive to crustal 1-D structure beneath the oceanic layer and thus can be used to probe the crust. This, in particular, means that the large amount of data that were not exploited for induction studies so far can be reconsidered as useful source of information at many observatories. Obviously quantitative interpretation of the tippers requires detailed and accurate information about bathymetry in the region of interest in order to adequately model nonuniform conductive oceanic layer.

107

SOME RESULTS OF SEISMO-ELECTROMAGNETIC RESEARCH AT LAPAN, INDONESIA

S. SAROSO 1, F. Nuraeni 1, I. Hilman 2

1. National Institute of Aeronautics and Space (LAPAN), Bandung, Indonesia 2. Dept. of Physics, Pajajaran University, Bandung, Indonesia

Indonesia is recognized as one of the most tectonically active regions in the world. This is evident in the number of earthquakes experienced by the country annually. Every year, Indonesia suffers extensive damage and loss of human life from earthquakes. To mitigate death and destruction on the islands of Indonesia, it is necessary that a way of making a “forecast” for earthquakes be developed. Recently, seismo-electromagnetic phenomena have been considered a promising tool for monitoring seismic activity. The presence of such precursory signature related to strong earthquakes has been identified in the anomalous ULF geomagnetic field change. There has been a good deal of accumulated and convincing evidence of ULF geomagnetic signatures before strong earthquakes as reported in the previous studies. Studies related with the pre-earthquake ULF geomagnetic anomalies are carried out at LAPAN in collaboration with Chiba University, The University of Electro-Communications, Nagoya University, and Kyushu University. Case studies are carried out in this work to investigate the pre-earthquake ULF geomagnetic anomalies during the Aceh earthquake on December 26, 2004 (magnitude Mw= 9.0 and depth = 30 km from USGS catalog), and Nias earthquake of March 28, 2005 (Mw= 8.7 and depth = 30 km). To investigate the pre-earthquake ULF geomagnetic anomalies, we have adopted the spectral density ratio analysis and transfer functions analysis based on wavelet transform method. Results of the spectral density analysis indicate similar variations to those of amplitude for the induction arrow in transfer function analysis. Both of these variations at Kototabang exhibit strange or anomalous changes from a few weeks before the Sumatra-Andaman earthquake to March 2005, while there are no apparent changes at remote station of Biak. To make these results more convincing, the fractal analysis have been applied to the same observed data, which also show a significant change in fractal dimension a few weeks before the earthquakes. This result would lend a further support to those by the polarization and transfer function analyses. We can conclude that the anomalous change as observed simultaneously by those methods, might be a possible signature related with the earthquake preparation phase of Sumatra earthquakes.

108

USGS GEOMAGNETISM PROGRAM PRODUCT SUMMARY

JL GANNON 1, CA Finn 1, JJ Love 1, DC Stewart 1, EA McWhirter 1

1. USGS Geomagnetism Program, Golden, CO, USA

The USGS Geomagnetism Program operates magnetic observatories across the United States, providing high quality, near real-time magnetic field measurements. These data are used for science applications and are also used as near real-time input to space weather models and indices. We describe the operational products being produced at the USGS from the real-time data, including 1-minute Dst, 1-minute K index, and local disturbance measurements. These products are used to specify and analyze geomagnetic storm conditions and can be used in space weather monitoring and operations. We also present additional USGS products under development, including hazard mapping, geomagnetic storm operational summaries, and ground level electric field estimates.

109

PERMANENT0GEOMAGNETICoOBSERVATORIESoNETWORK, IGRF, GEODYNAMICS AND SUN-EARTH CONNECTION.

J.C. GIANIBELLI 1

1. Departamento de Geomagnetismo y Aeronomía, Facultad de Ciencias Astronómicas y Geofisicas, UNLP, Paseo del bosque, 1900 La Plata, Argentina, geofisicogianibelli@yahoo.com.ar

The IGRF model is a multipolar expression of a geodynamo at the surface of the Earth. The information of permanent geomagnetic observatories of their annual mean values are compared with those of IGRF. The calculated residual secular variation shows changes that could be related to geodynamic processes in regions of deep earthquakes. Likewise the IGRF secular variation obtained from sample variations of periods related to the Sun-Earth connection. This paper shows geodynamic phenomena by studying the source of information produced by the Permanent Geomagnetic Observatory surrounding the subducted Nazca Plate. It also presents the results of time series analysis of the secular variations of a profile North Pole-South Pole. We conclude that Earth's mantle has important inductive aspects as also the outer core of the Earth.

110

THE STRUCTURE OF SOLAR-GEOMAGNETIC DISTURBANCES AND THE DYNAMICS OF ATMOSPHERE

SPOMENKO J. MIHAJLOVIĆ 1, Rudi Čop 2

1. Republic Geodetic Authority, Blvd. V. Mišića 39, 11000 Belgrade, SERBIA, e-mail: mihas@sezampro.rs 2. Higher Education Center Sezana, Laboratory for Geomagnetism and Aeronomy, Kraška ulica 2, 6210 Sežana, Slovenia, e-mail: rudi@artal.si The results of different solar and climatological researches, show connection between solar geomagnetic activity changes (SGMA), electromagnetic environmental field changes (EEMF) and meteorological parameters (MP) changes. Changes of SGMA, EEMF and MP could be seasonal, yearly or long periodic, cyclic changes. In this work will be shown and analyzed geophysical processes which determinate the SGMA disturbances. Those are occurrences of intensive solar flares (Sun's hromospheric eruptions), solar and magnetic storms. In period 1986-2010, during 22nd, 23th and 24 Sun's cycle, class of Big Magnetic Storms are registered (about ten storms). In first phase of analyze are observed regular daily geomagnetic field variations in month when is registered geomagnetic disturbance. In next step of the analyze, in each of mentioned Big Magnetic Storm, are observed groups of apperiodical or irregular geomagnetic field variations. That is shown by groups Dst and Di geomagnetic field variations. Analyze of structure geomagnetic field variations is done on several European observatories of the middle geomagnetic latitude. For months and days when the intensive solar and magnetic storms are registered, changes of the meteorological parameters will be analyzed. We will present distribution of hourly mean values of air temperature for magnetic quite days (Q-days) and for magnetic disturbed days (D-days), in months when the Big Magnetic Storms are registered. Assignment of hours values of the air temperature and the number sunshine interval before, during and after the SGMA disturbance will be observed. The results of analyzes of changes the SGMA indices and the meteorology parameters, will be applied to researching of the climate and meteorology process (the atmosphere /weather situation progress). In this researches (study) will be shown the connection between the SGMA indices changes and the structure of the atmosphere / weather situations.

111

SOLAR ACTIVITY EFFECT ON MEASUREMENTS OF THE ITALIAN MAGNETIC NETWORK

R. TOZZI 1, G. Dominici 2, P. De Michelis 3, A. Meloni 4

1. Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy, roberta.tozzi@ingv.it 2. Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy, guido.dominici@ingv.it 3. Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy, paola.demichelis@ingv.it 4. Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy, antonio.meloni@ingv.it

The influence of solar activity on magnetic measurements taken during the Italian repeat station surveys performed in 1999/2000 and 2009/2010 has been investigated. A method to estimate the difference between the 2000.0 and 2010.0 surveys in terms of the “residual” (i.e. not completely reduced) external contribution is proposed. This method is also based on the removal of the contribution due to the magnetic field of internal origin by means of CHAOS3 model from magnetic repeat station measurements. The origin of the observed differences is interpreted in terms of the very different level of solar activity between 2000.0 and 2010.0. Indeed, results seem to suggest that differences could be attributed to the enhanced ring current intensity during a phase of solar maximum. The investigation of the spatial patterns of these differences suggests that they could be reduced by introducing a larger number of variometer stations, especially during surveys undertaken under conditions of high solar activity.

112

GEOMAGNETIC MONITORING OF THE 2011-2012 VOLCANIC ERUPTION IN EL HIERRO (CANARY ISLANDS, SPAIN)

V. Villasante-Marcos 1, B. Casas-Delgado 2, R. Abella 1, M. J. Blanco 2, B. Brenes 1, V. M. Cabrera-Rodríguez 2, I. Domínguez-Cerdeña 2, A. Felpeto 1, M. Fernández de Villalta 1, C. del Fresno 1, M. J. García-Arias 1, L. García-Cañada 1, A. Gomis-Moreno 1, E. González-Alonso 1, J. Guzmán-Pérez 2, I. Iribarren 2, C. López 1, R. López-Díaz 1, N. Luengo-Oroz 1, S. Meletlidis 2, M. Moreno 2, D. Moure 2, J. Pereda de Pablo 2, C. Rodero 2, E. Romero 2, S. Sainz-Maza 1, M. A. Sentre-Domingo 1, P. A. Torres 2, P. Trigo 1, J. M. Tordesillas 3

1. Observatorio Geofísico Central, Instituto Geográfico Nacional, Observatorio del Retiro, C/ Alfonso XII, 3, 28014 Madrid, Spain. 2. Centro Geofísico de Canarias, Instituto Geográfico Nacional, C/ La Marina, 20, 2º, 38001, Santa Cruz de Tenerife, Spain. 3. Servicio de Geomagnetismo, Instituto Geográfico Nacional, C/ General Ibáñez de Ibero, 3, 28003 Madrid, Spain.

Starting on July 2011, El Hierro Island experienced an episode of volcanic unrest with ~12000 earthquakes and ground deformations of ~4 cm. This reactivation culminated in a submarine eruption 2 km off-shore the southern tip of the island, starting on 10th October 2011 and finishing on March 2012. This is the first eruption in El Hierro at least since the XVIII century and the first eruption in the Canaries monitored by a complete geophysical network of seismometers, GPS, magnetometers, gravimeters, geochemical stations and measurement of CO2 flux and groundwater geochemistry. Within this monitoring effort was a network of two GSM-19 Overhauser and two G-856 proton magnetometers which started operations on 7th September, 2011. These instruments have registered the total geomagnetic field intensity (F) at different points of the island. Their comparison has allowed us to investigate the magnetic effects of the volcanic unrest and activity. Although the lack of a previous baseline of comparable observations difficults any interpretation, an acceleration of F-variation is observed in correlation with deformation and seismic energy liberation curves before the eruption, probably indicating long-term piezomagnetic and/or electrokinetic effects linked to ground deformation. In contrast, no clear short-term magnetic variations are observed at the beginning of the eruption. Thus, any short-period magnetic effect of the eruption must be quite local and limited to distances lower than the distance between the new eruptive centre and the closest magnetic station.

113

GEOMAGNETIC OBSERVATION AT MERIDIAN STATIONS IN CHINA

X.Z. WANG 1, Y.T. Teng 1, D.M. Yang 1

1.oInstitute of Geophysics, China Earthquake Administrator

Minzudaxue Nanlu No.5, Beijing 100081, China.

wxz9288@yahoo.com.cn

In this paper, it was used the geomagnetic data from Meridian Stations in China to study

the magnetic storm in Jan.24, 2012.

Meridian Project, namely the Grand National Science and Engineering Infrastructure on

space weather monitoring, had been constructed by China government from Jan. 2008

to Dec. 2010. The Meridian Project is the ground-based network program to monitor

solar-terrestrial space environment, which is consisted of one chain of 15 ground-based

observatories with multiple instruments including magnetometers, ionosondes, HF and

VHF radar, Lidar, IPS monitors, sounding rockets etc, which mainly located in the

neighborhood of 120°E meridian.

114

Keynotes

 

116

SPACE WEATHER APPLICATIONS OF GEOMAGNETIC OBSERVATORY DATA

ALAN W. P. THOMSON 1 1.oBritish Geological Survey, West Mains Road, Edinburgh EH9 3LA, UK, awpt@bgs.ac.uk

Solar maximum is expected between late 2012 and early 2014. Space weather impacts on worldwide technological infrastructures are therefore likely to be at their greatest at this time. These infrastructures include power grids, pipelines, railways, communications, satellite operations, high latitude air travel and global navigation satellite systems. For example, severe magnetic storms in March 1989 and October 2003, near the peaks of previous solar cycles, were particularly significant in causing problems for a wide variety of technologies. Further back in time, severe storms in September 1859 and May 1921 are known to have been a problem for the more rudimentary technologies of the time. In this talk I will review what these impacts are, what scientific research and measurement is underway, or is still needed, and how the observatory community can best contribute to the ongoing efforts in developing new space weather data products. Examples of existing and perhaps some suggestions for new data products will be given. Throughout the need for near to real time observatory data and products to help space weather forecasters and to serve industry and government will be emphasised. I will also discuss how industry perceives the space weather hazard, using examples from the electrical power industry, concerned with the risk to high voltage transformers and the safe and uninterrupted distribution of electrical power.

117

NEW INSTRUMENT DEVELOPMENTS FOR GEOMAGNETIC OBSERVATORIES

MONIKA KORTE 1

1.oHelmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany, monika@gfz-potsdsam.de

Geomagnetic observatories are the backbone for studying geomagnetic secular variation and thus to provide insights into the geodynamo process. They are a valuable complement to modern satellite missions, which offer a better global coverage, but at the cost of mixing spatial and temporal magnetic signal in the data series. The different spatio-temporal characteristics of magnetic satellite mission and geomagnetic ground observatory data are ideed ideal counterparts for many scientific studies. Moreover, observatories can provide much longer time-series and fill temporal gaps between individual satellite missions. The most important requirement for high quality magnetic observatories is the long-term stability of the data series, reflecting accurately the true, long-term secular variation without any environmental or instrumental change influences. Nevertheless, improvements to provide higher data accuracy or resolution according to evolving measurement technology advances have to be implemented. Moreover, in order to fill gaps in the global network, low-cost and mostly automated geomagnetic observatories are desirable. Traditionally, variometer recordings are combined with an adopted baseline obtained from manually performed absolute measurements to produce a continuous observatory data series. In many cases, the variometer is a three-component fluxgate magnetometer, and an additional Overhauser scalar magnetometer is operated at the observatory. The stability of the baseline and the comparison between intensity recordings from e.g. an Overhauser magnetometer and calculated from a three-component fluxgate magnetometer can serve as indicators for data quality. Several ideas to replace or reduce the need for manual absolute measurements are under development by different groups. They can broadly be divided into two approaches: firstly, there are attempts to automate (or at least facilitate) the regularly performed absolute measurements. Secondly, efforts are made to build more stable vector magnetometers, e.g. based on inherently stable absorption cell magnetometers to which additional fields are applied in order to obtain component recordings. I review and summarize these approaches and discuss their influence on how geomagnetic observatories might evolve in the future.

118

GROUND OBSERVATORIES AND SATELLITES – TWO COMPLEMENTARY SOURCES FOR EXPLORING THE EARTH’S MAGNETIC FIELD NILS OLSEN 1 1 . DTU Space, National Space Institute, Technical University of Denmark, JulianeMariesVej 30, 2100 Copenhagen, Denmark The spatial distribution of geomagnetic ground observatories is rather uneven, with large gaps in the oceans. A global description of the geomagnetic field is therefore not possible from ground data alone.Although considerable efforts have been made recently to fill some of the gaps by installing observatories at remote islands, a true global survey of the geomagnetic field is only possible with satellites. Butsatellites move at approximately 8 km/s, and it is therefore not possible to decide whether an observed magnetic field variation is due to a temporal or spatial change of the field. This situation is rather different formagnetic measurements taken by observatories at fixed locations on the ground, for which an observed variation can always be attributed to a true temporal change of the field. In this talk I will review the fundamental difference between data from geomagnetic observatories and satellites and their advantages and shortcomings for studying the geomagnetic field. I will also discuss how geomagnetic field modeling efforts take advantage from combining these two data sets and aboutthe changing role of ground data for exploring Earth’s magnetic field during the satellite era.

 

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