Multi-satellite Solar Spectral Irradiance

Composite (MUSSIC)

M. Snow, J. Machol, & E. Richard

University of ColoradoLASP & CIRES

snow@lasp.colorado.edu

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Outline

• UV Solar Spectral Irradiance Datasets• Magnesium II Proxy for SSI • Plans for SSI Composite• EUV Measurements & Models• Plans for distribution of MUSSIC

This work was supported by NASA Cooperative Agreement NNX13AI25A with the University of Colorado under the

Making EArth science data records for Use in Science Environments (MEAsURES)

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Observations Summary

GOME-2

SDO EVE

“EUV Hole”

“FUV Hole”

GOES-13GOES-14GOES-15

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Typical Time Series (good)

2%

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Typical Time Series (evil)

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Merging Instrumental Records

• Absolute calibration offsets• Drifts in calibration (degradation)• Gaps

• Guidance from Proxies• Guidance from Models

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UV Proxy: Magnesium II Index

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Scaling during overlap

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Correct artifacts in Proxy

Snow et al. (2013) submitted to Space Weather Space Climate

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Updated MgII Composite: Snow et al. 2014 (in

preparation)

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Select Overlap

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Find Scaling

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Adjust

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Repeat

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Encore!

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Noch Einmal!

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Select epoch for each

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Et Voila!

• Each instrument/channel will require evaluation for calibration, epoch, etc.

• Propagation of measurement and systematic errors will require analysis.

• Wealth of datasets in FUV (120-180 nm) and MUV (180-320 nm) will add confidence to the result.

• EUV observations are more scarce.

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Filling the EUV Hole (pre-2002)

• Based on measurements from TIMED SEE and SORCE SOLSTICE, the Flare Irradiance Spectral Model (Chamberlin 2007) can provide a daily estimate of EUV spectrum (1947-present).

• Working group on EUV empirical modeling intends to meet monthly in Boulder (with tele/Skype participants welcomed): eparvier@lasp.colorado.edu

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GOES EUVS• GOES 13, 14, and 15 measure the EUV with five

broadband sensors (2006 onwards).– GOES-15 E channel available from Janet now– Calibrated data from other channels available in future

• GOES-R series has only 3 bands, but spectrally resolved.

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GOES EUV Proxy model

Provides 1-minute cadence and daily average in the 22 “Stan bands” (Solomon & Qian, JGR, 2005).

Model is derived from a linear combination of the five EUVS bands, two XRS channels, Mg II index, and F10.7

planned

actual

0 20 40 60 80 100

1E-6

1E-5

1E-4

Irra

dia

nce

(W

/m2

)

Wavelenth (nm)

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

Irra

dia

nce

(W

/m2

)

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GOES vs SDOSDO EVE Data

GOES EUV Model

Day of Year in 2012

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GOES vs SDO (2)SDO EVE Data

GOES EUV Model

Poor agreement for wavelengths longer than 50 nm may be due to uncertain degradation correction for MEGS-B on EVE.

Plots courtesy of R. Viereck

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How Well Does It Do?• The correlation between

the modeled spectrum and the observed spectrum for the year 2012.

• Correlations – 0.7 to 0.99 for new model– 0.6 to 0.9 using MgII alone– 0.5 to 0.8 using F10 alone

• EUV driven model is a clear improvement over F10 or MgII driven proxy models.

Daily average product will be available from NOAA in early 2014

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MUSSIC Distribution

http://lasp.colorado.edu/lisird

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Summary/Plans

• Multisatellite Ultraviolet Solar Spectral Irradiance Composite (MUSSIC) will create EUV and UV data records for distribution through LISIRD.

• Composite MgII in 2014• Composite SSI over the next few

years