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Comparisons of Solar and Dayglow Q EUV

Comparisons of Solar and Dayglow Q EUV. R. R. Meier 1 , J. L. Lean 1 , D. J. Strickland 2 , A. B. Christensen 3 , T. N. Woods 4 , F. Eparvier 4 , D. McMullin 1 , D. L. Judge 5. 1 Naval Research Laboratory, Washington D.C. 2 Computational Physics, Inc, Springfield, VA

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Comparisons of Solar and Dayglow Q EUV

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  1. Comparisons of Solar and Dayglow QEUV R. R. Meier1, J. L. Lean1, D. J. Strickland2, A. B. Christensen3, T. N. Woods4, F. Eparvier4, D. McMullin1, D. L. Judge5 1 Naval Research Laboratory, Washington D.C. 2 Computational Physics, Inc, Springfield, VA 3 Aerospace Corporation, El Segundo, CA 4 LASP, University of Colorado Boulder, Boulder, CO 5 University of Southern California., Los Angeles, CA TIMED /QEUV STM SWRI SEP 2004

  2. TIMED Solar and Terrestrial Observations - SEE solar EUV irradiance - GUVI FUV dayglow Solar-Upper Atmosphere Radiative Coupling Solar EUV Irradiance Variability Terrestrial FUV Dayglow - QEUV… energy to produce FUV dayglow - disk, limb & solar measurements and models Comparisons of Solar and Dayglow QEUV - solar rotation (andcycle), solar flares Outline

  3. TIMED Measures Solar EUV Radiation and FUV Dayglow Simultaneously SEE measures solar EUV irradiance energy input in 1 nm bins FUV EUV Photoelectron-excited Dayglow H O O N2 N2 GUVI measures FUV dayglow spectra in five “colors” HI Lyman  119.3 – 123.7 OI 130.4 nm OI 135.6 nm 128.4 – 131.8 134.2 – 137.7 N2 LBH short N2 LBH long 141.0 – 152.8 167.1 – 181.2

  4. QEUV: The Energy Required to Produce the FUV Dayglow minimum energy to produce FUV dayglow ~ 27 eV ~17 eVfor photoionization ~ 10 eV for electron excitation EUV photons   450 Å disk limb GUVI measures FUV dayglowemission between about 100 and 300 km - I1356 & ILBH from solar EUV spectrum used in algorithm Modeling of disk dayglow by Strickland et al. (JGR 1995): I1356 ~ [O]column × QEUV ILBH ~ [N2]column × QEUV [I1356/ILBH] ~ [O/N2]column observed dayglow dayglow as a function of [O/N2]column and zenith angle

  5. Daily Mean Solar EUV Irradiance TIMED SOHO/SEM central order data Solar Cycle 23 EUVAC model SEE V7 data NRLEUV model HFG model SEE__L3_merged_2004243_007 SEM X 8.3495E-11

  6. Solar 5 nm Binned Fluxes daily means

  7. GUVI FUV Dayglow Observations one day one revolution Rev 3550 O/N2~ composition QEUV~energy

  8. GUVI and Solar QEUV Daily Variations daily means SEM central order 0-45 nm SEE 0-45 nm HFG 0-45 nm but many missing soft X-ray lines NRLEUV 5-45 nm × 1.15 NRLEUV ~ 50% decrease from 2002 to 2004

  9. SEE and GUVI QEUV Daily Ratios daily means July-Aug Oct-Nov

  10. GUVI and Solar QEUV Variations: July-August 2002 QEUV daily mean values EUVAC SEE SEM HFG Jul-Aug 2002 GUVI -limb +50% GUVI-disk NRLEUV QEUV daily mean ratios HFG EUVAC NRLEUV SEE Absolute Uncertainties: GUVI  15% SEE  10% - goal NRLEUV  50% GUVI -limb GUVI-disk SEM updated from Strickland et al., GRL, 2004

  11. GUVI and Solar QEUV Variations: October-November 2003 Rotations QEUV daily mean values SEE EUVAC SEM GUVI -limb GUVI -disk NRLEUV HFG Oct-Nov 2003 QEUV daily mean ratios SEE GUVI -disk HFG SEM GUVI -limb NRLEUV

  12. GUVI Dayglow Enhancements During Solar Flares flare clusters of GUVI QEUV per orbit: each point within a cluster is an average over 14 along-track spatial pixels and 13 cross-track pixels Strickland et al., GRL, 2004

  13. GUVI and Solar QEUV Variations During Solar Flares - per rev (20 mins) • per min  3 mins

  14. GUVI and Solar QEUV Variations: October-November 2003 28 OCT 28 OCT 4 NOV 18 NOV QEUV 4 NOV

  15. GUVI and Solar QEUV Variations: 18 November 2003

  16. GUVI Disk and Limb QEUV Differences EUV energy at different wavelengths is deposited at different altitudes disk limb disk and limb view airglow from slightly different altitude regimes QEUV is derived by scaling the EUV and X-rays fluxes input to AURIC: limb signal is less sensitive than disk to  < 20 nm → upper limit of QEUV limb disk

  17. 4NOV03 Summary: SEE and GUVI QEUV • ABSOLUTE LEVELS: • - GUVI QEUV is about half as bright as SEE and SEM - increase needed for Hinteregger fluxes < 20 nm? VARIABILITY: • - detailed tracking during solar cycle, rotation, flares • - QEUV decreased 50% from Jan 2002 to Dec 2003 • - GUVI QEUV has factor of 3 smaller increase in flares than SEE • …. GUVI QEUV increases are similar to SEM • - TIMED orbit prevents observing all flares, all rotations • FUTURE: • - limb versus disk differences have spectral information • - SDO/EVE 10 sec EUV spectra; global FUV imager needed

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