The Purposes of Synoptic Observations

Synoptic Network Workshop, Boulder, April 2013

Oskar von der LüheKiepenheuer-Institut für Sonnenphysik, Freiburg

Synoptic observations have a long tradition

• The first modern solar physicist: Galileo proposed the solar origin of sunspots

Sunspot drawings by Galileo from 1613 (Rice Galileo Project)

What are synoptic solar observations?

• Time-resolved measurements of a physical characteristic of the Sun– with a scope of the entire solar disk and the solar space environment– with a scope of long time periods– often with high cadence (minutes)

• Similar paradigms – repeated measurements of large volumes of targeted and untargeted astrophysical quantities with long duration and high cadence - now enter nighttime astronomy where they are called “time domain astrophysics” and create billion-$ projects

ADS KW search: (sun | solar) & synoptic

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False PositivesPubl. / Year

Examples of synoptic observationsNSO/GONG Udaipur

H Intensity

2012/02/14

GONG, MDI, AIA, MSFC, SOLIS, LASCO, PMOD, SWPC

Role of contemporary solar physics• Distinct field of research since the introduction of stellar

spectroscopy in the 19th century– Leading stellar spectroscopy for many decades, still leading in polarimetry– Leading in theoretical understanding of stellar atmospheres– Only discipline in astrophysics which has direct impact on modern

civilization• The “Easy Experiments” have mostly already been done

• Big steps of discovery and understanding of the Sun which result from simple experiments require new technologies

• Nobel Prize level discoveries are not likely• Progress means hard and tedious work

– Advanced technology, techniques and methods in theoretical and experimental solar physics

Role of contemporary solar physics

Solar Physics

Stellar Physics

(non-stellar) Astrophysics

Terrestrial Physics

Fundamental Physics

Stellar dynamosStellar structureExoplanets

Particle physicsGeneral relativity

Cosmic magnetic fieldsAbundances

Flares and CMEsSolar „constant“

Role of contemporary solar physics – relation to stellar physics

• Stellar physics has reached a similar level of maturity as has solar physics

• Currently active links are stellar magnetic activity and asteroseismology

• Stellar physics has experienced a tremendous boost since the discovery of exoplanets

• Advances in Stellar physics reflect back on Solar physics

C. Schrijver / LMSARL

Role of contemporary solar physics – solar-terrestrial relations

• Monitoring of solar activity and energetic events is essential for spacecraft operations

• Impact of solar activity on the Earth‘s magnetic field may impact large infrastructures

• Predicting solar activity, solar energetic events and their impact in Earth is the bread-and-butter raison d'être for solar research

Stereo A

WSA-Enlil (NOAA)

Solar Physics in the 21st Century – scientific questions

• How is the solar magnetic field generated, maintained and dissipated?– Discriminate solar dynamo models– Determine the role of induction effects near the surface for the global field– Determine the characteristics of angular momentum transport inside the Sun– Observe, identify and characterize magnetic reconnection

• How does solar magnetism influence the internal structure and the luminosity of the Sun?– Compare the Sun with stars with differ in magnetic activity through asteroseismology – Determine impact on exoplanet detection and characterization

• How are the solar corona and the solar wind maintained and what determines their properties?– Observe, identify and characterize acoustic and magneto-acoustic waves in the upper

atmosphere

• What triggers transient energetic events?– Determine the role of the interaction of interior flow and magnetic fields– Establish reliable space weather prediction

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Which observing capabilities are needed to address current and future science questions?

• Detailed studies of magnetic field and plasma physics processes in the solar atmosphere including the corona– Consistently highest spatial, temporal and spectral resolution– High sensitivity, very high SNR– Modest fields of view and temporal coverage– Access to a large part of the electromagnetic spectrum

• Comprehensive studies of large to medium scale processes in the solar interior and atmosphere including the corona– Medium/high spatial resolution, limited spectral resolution and/or coverage,

selected spectral lines– Full solar disk, entire electromagnetic spectrum– Long term uninterrupted temporal coverage

Several large aperture telescopes on the ground and in space

Small to medium aperture ground based networks and space facilities

Why do we need large solar telescopes?

Numerical simulation (M. Rempel, HAO) Observations with GREGOR (v. d. Lühe, KIS)

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New Large Solar Telescopes

Advanced Technology Solar Telescope

4m USA

BBSO New Solar Telescope

1.6m USA

Design Construction Commissioning

Yunnan Obs. Solar Telescope

1m China

National Large Solar Telescope

2m India

Gregor

1.5m D/ES

European Solar Telescope

4m EUR

Purposes of synoptic observations• How is the solar magnetic field generated, maintained and dissipated?

– Discriminate solar dynamo models– Determine the role of induction effects near the surface for the global field– Determine the characteristics of angular momentum transport inside the Sun– Observe, identify and characterize magnetic reconnection

• How does solar magnetism influence the internal structure and the luminosity of the Sun?– Compare the Sun with stars with differ in magnetic activity through asteroseismology – Determine impact on exoplanet detection and characterization

• How are the solar corona and the solar wind maintained and what determines their properties?– Observe, identify and characterize acoustic and magneto-acoustic waves in the upper

atmosphere

• What triggers transient energetic events?– Determine the role of the interaction of interior flow and magnetic fields– Establish reliable space weather prediction

Synoptic facilities - Space

• Space missions offer unique opportunities– Access to the entire e.

m. spectrum– Absence of detrimental

impact of the Earth‘s atmosphere

– Stable conditions and very consistent data

Stereo

SoHO

Hinode

Solar Dynamics Observatory

Solar facilities - Ground

• Ground based observatories offer unique opportunities:– Large telescopes and

instruments– Flexibility– High data rates

GREGOR/KIS

Synoptic facilities – Space vs. Ground

• There is no synoptic measurement which cannot in principle be done from space– many measurements can only be done

from space• Limiting factors for space missions are

cost and telemetry– ground missions are required to get the

complete picture• Solar physics has a fair share of space

missions• Scientific goals and data products of

space and ground missions must complement and be well aligned– Redundancy is part of that

Solar Dynamics Observatory

PMOD/WRC

Solar observing facilities - Ground

Synoptic Realm

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Networks for helioseismology and space weather prediction

GONG BiSON SOON

Solar Physics in the 21st Century – Synoptic networks

• Future solar networks should provide:– Velocity maps at different heights – Maps of vector magnetic fields at different heights– Maps of quantities relevant for space weather– At multiple wavelengths– With high cadence, duty cycle and lifetime– With high sensitivity to velocity and magnetic fields– Complement space missions

Solar Physics in the 21st Century – Synoptic networks

• Operating even a small network (BISON, GONG) is a big effort for a national community

• Designing, deploying and operating a distributed, comprehensive, ground based network requires a new level of international collaboration– SOLARNET - SPRING

• Opportunity to involve and sustain smaller research groups in solar physics

What else do we need?Data management and archiving

• Synoptic facilities on the ground and in space produce large amounts of data which must be digested to produce useful products

• Procedures for data calibration, reduction and archiving are similar, if not the same– MDI and GONG share a lot of data reduction procedures

• Space projects come with data management funding• Ground facilities share these needs and also require

adequate funding

What now are the purposes of synoptic observations?

• Solar physics is relevant because of its societal impact• Synoptic solar observations are essential for

answering relevant key questions– Both space and ground facilities are indispensible. They

must be complementary– Future ground based networks should be an international

endeavor• The importance of synoptic observations is veiled by

the visibility of large projects which has adverse effects on funding