Operational ground-based remote sensing of windOperational ground-based remote sensing of wind

Experiences from the European wind profiler network CWINDEExperiences from the European wind profiler network CWINDE

V. Lehmann1, A. Haefele2, S. Klink4, G. Martucci2, M. Hervo2, M. Turp3, Eileen Päschke1, R. Leinweber1

1 - Deutscher Wetterdienst2 - MeteoSwiss

3 - UK MetOffice4 - EUMETNET Observations Programme

Outline of talk

1.Radar Wind Profilers and their operational use in the EUMETNET E-PROFILE Programme – CWINDE

2.Benefits: RWP data impact in Numerical Weather Prediction

3.Challenges: Current and future tasks for E-PROFILE

1.Radar Wind Profilers and their operational use in the EUMETNET E-PROFILE Programme – CWINDE

2.Benefits: RWP data impact in Numerical Weather Prediction

3.Challenges: Current and future tasks for E-PROFILE

WMO Statement of Guidance for high resolution NWP (May 2012):

„The critical atmospheric variables that are not adequately measured by current or planned systems are (in order of priority)“

1. Wind profiles at all levels (u,v)2. Temperature and humidity profiles of adequate vertical

resolution in cloudy and rainy areas3. Precipitation4. Snow equivalent water content5. Soil moisture

http://www.wmo.int/pages/prog/www/OSY/GOS-RRR.html

„Clear air“ Doppler radars – wavelenghts 0.2 – 6 m

Horizontal wind vector (u,v), virtual temperature Tv

1.) Mature technology: - First demonstration in early 1970‘ies - Operationally used since mid 1990‘ies - (Most) operationally relevant problems solved 2.) All-weather 24/7 operation

data in both clear and cloudy atmosphere (!)

3.) Availability - Commercial vendors existing

4.) Practicality - RF Spectrum assigned by WRC - Interference issues must be considered

Radar wind profiler (L-Band to VHF)

EUMETNET E-PROFILEEUMETNET E-PROFILECoordinated WIND profiler network in Europe (CWINDE)

http://www.metoffice.gov.uk/science/specialist/cwinde/profiler/

A network for operational profiling of wind and aerosol

Runs under EUMETNET, a grouping of 31 European NMS’s: 1.1. 2013 - 31.12. 2017

19 (out of 31) members - responsible: MeteoSwiss

Co-operative network, no central funding for sites

EUMETNET E-PROFILE – some factsEUMETNET E-PROFILE – some facts

www.eumetnet.eu/e-profile

Wind profiling network - CWINDE (operational)

42 RWP :

VHF: 16 (including 11 O-Q network radars in Canada)

UHF: 4 (Germany, 482 MHz)

L-Band: 22 (including La Reunion and Samoa)

107 „weather radars“ (mostly C-Band): VAD, VVP wind data

Aerosol profiling network (under development)

1. New capabilities (instruments)

recent ceilometer generation backscatter contains information on aerosols and clouds

Automatic Laser Ceilometer (ALC) network

2. Suitability for network operation

Low costsUnattended 24/7 operation Most instruments already deployed

Future E-PROFILE ceilometer network

Extended remit of E-PROFILE:Inclusion of laser ceilometers

Network integration and data harmonization needed

CWINDE Performance targetsCWINDE Performance targets

1. Data availability

≥ 85 % (≥ 95 % internal goal)

2. Message timeliness

Observation time + 30 minutes: ≥ 95 %

3. Measurement accuracy (estimated from ECMWF IFS):

integral RMS vector difference: ≤ 5.0 m/s

Monitoring: Quality (against NWP)

Vertically averaged statistics: VD – vector difference, WS - wind speed, (U,V)T – horizontal wind vector

11

Monitoring: Availability & Timeliness

AVL: Availability, Δ30: Timeliness (t + 30 min), Δ60: Timeliness (t + 60 min)

1.Radar Wind Profilers and their operational use in the EUMETNET E-PROFILE Programme – CWINDE

2.Benefits: RWP data impact in Numerical Weather Prediction

3.Challenges: Current and future tasks for E-PROFILE

FSACost/benefit considerations for RWP

NOAA report from May 2004:

“The NOAA profiler network provides the best overall wind profile performance since no alternative provides equal or higher performance at lower costs”

http://www.nws.noaa.gov/ost/coea/COEA_May26_final.pdf

However, OSE impact studies performed by various NWP Centres had so far given quite mixed results: “overall weakly positive or neutral impact”

Probable reasons: Small total number of RWP“Good and bad” lumped together

FSAModel state vector, dimension O(108)

Norm of the state vector – „energy measure“:

Forecast error of two forecasts starting at t-6 h and t=0.

The difference of the two forecast errors at t +24 h is approximately only due to thenew observations ingested at t = 0

Estimation of RWP observation impact in NWP – Adjoint sensitivity estimates (FSO)

„Innovation x Observation sensitivity“:involves only observation space quantities

Allows partitioning of forecast error reduction for each observation

Langland and Baker (2004) „Estimation of observation impact using the NRL variational data assimilation system“, Tellus 56A, 189-201

„Observation sensitivity calculation requires:(1)Adjoint of forecast model (TL)(2)Adjoint of data assimilation system

Observation contribution to the global forecast error reduction (FEC) in the ECMWF IFS, grouped by observation type in percent, for September and October 2011.

Courtesy of C. Cardinali, ECMWF.

Total FEC. Mean FEC

(normalized by # of observations)

ECMWF FSO estimate of observation impact

Deutscher WetterdienstUK MetOffice FSO estimate of RWP impact

Reduction of forcast error measured by global moist energy norm (u,v,T,p,q)

4 German TEMPs vs.

4 German RWP (482 MHz)

First results from UK MetO FSO-tool for the period

Aug 22 – Sep 29, 2010

Courtesy:

Richard Marriott

Catherine Gaffard

Ronny Leinweber

Lindenberg RWP impact is 5 times bigger than the impact of the co-located Radiosonde !

1.Radar Wind Profilers and their operational use in the EUMETNET E-PROFILE Programme – CWINDE

2.Benefits: RWP data impact in Numerical Weather Prediction

3.Challenges: Current and future tasks for E-PROFILE

Deutscher

1. Protection of frequencies: Need bands without interfering RF signals

2. Qualified staff crucial – maintain existing knowledge through training and workshops

3. Enforce strict quality control at the sites – “no data is better than bad data” Clutter filtering – many algorithms are existing, bub not always implemented Detection of non-homogeneous wind field conditions – convection, gravity waves,…

4. Hardware and software maintenance:1. Radars operate over 10+ years – need for renovation or replacement2. Continuous evolution of operating systems – IT security

5. Development and automation of monitoring1. System failures must be identified quickly2. Standardization of RWP “raw data” formats (moments, spectra, I/Q) 3. NWP monitoring statistics – development of unified graphics (results from different models)

• Exploit potential of new IR Doppler lidars for Boundary-Layer wind profiling Implementation of new WMO BUFR template for wind observations in 2015

Challenges for E-PROFILE (and RWP)Challenges for E-PROFILE (and RWP)

Lidar wind profiler (IR)

Radial wind data from a 24 beam VAD-scan, Oct 03, 2012 08:20 -09:20 UTC

Horizontal wind vector (u,v)

1.) Maturity: - First demonstration in mid 1960‘ies (CO2 laser)

- Wind shear warning systems since mid 2000 - Testing in operational setting under way 2.) All-weather 24/7 operation: Yes, limited availability

- in and above optically thick clouds - in particle-free atmosphere (no targets)

3.) Availability - Commercial vendors existing - Market currently very active (mainly wind energy)

4.) Practicality - Easy to deploy, fully autonomous operation - All-fiber optics: Mechanically very stable - Eye safe (Laser class 1M)

Data availability: Radar vs. Lidar wind profiler (quality controlled data

only)

482 MHz RWP, 1 µs pulse, “Low mode”

1. 5 µm Lidar, 160 ns pulse

Oct. 02, 2012 – Oct. 02, 2013max # : 17568

482 MHz radar vs 1.5 µm lidar: 1-year intercomparison statistics

Summary

1. More wind profile observations are needed for high resolution NWP

2. Radar wind profiling is an existing and proven technology that can provide such data with good quality and high temporal resolution.

3. A clear positive impact of RWP data has been demonstrated using the new (adjoint based) sensitivity estimation method.

4. The EUMETNET E-PROFILE Programm continues to operate the CWINDE profiler network in a cooperative manner. The biggest challenge is the sustainability of CWINDE network profilers over 10+ years.

5. New IR-Doppler lidars can be used to complement the radar measurements in the Boundary Layer.

6. RWP (networks) will be a valuable reference for future space based sensors, like ESA‘s ADM Aeolus.

Meteorologisches Observatorium Lindenberg – Richard-Aßmann-Observatorium (2011)Meteorologisches Observatorium Lindenberg – Richard-Aßmann-Observatorium (2011)Meteorologisches Observatorium Lindenberg – Richard-Aßmann-Observatorium (2011)Lindenberg, Sep 03, 2011: Aerial view of 482 MHz RWP

Thank you !