Multi-satellite Solar Spectral Irradiance Composite (MUSSIC) M. Snow, J. Machol, & E. Richard University of Colorado LASP & CIRES

Outline UV Solar Spectral Irradiance Datasets Magnesium II Proxy for SSI Plans for SSI Composite EUV Measurements & Models Plans for distribution of MUSSIC 2 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)

Observations Summary GOME-2 SDO EVE “EUV Hole” “FUV Hole” GOES-13 GOES-14 GOES-15 3

Typical Time Series (good) 4 2%

Typical Time Series (evil) 5

Merging Instrumental Records Absolute calibration offsets Drifts in calibration (degradation) Gaps Guidance from Proxies Guidance from Models 6

UV Proxy: Magnesium II Index 7

Scaling during overlap 8

Correct artifacts in Proxy Snow et al. (2013) submitted to Space Weather Space Climate 9

Updated MgII Composite: Snow et al (in preparation) 10

Select Overlap 11

Find Scaling 12

Adjust 13

Repeat 14

Encore! 15

Noch Einmal! 16

Select epoch for each 17

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 ( nm) and MUV ( nm) will add confidence to the result. EUV observations are more scarce. 18

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): 19

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. 20

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 actua l 21

GOES vs SDO SDO EVE Data GOES EUV Model Day of Year in

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 23

How Well Does It Do? The correlation between the modeled spectrum and the observed spectrum for the year 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

MUSSIC Distribution 25

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 26