1. EUV Irradiance Reconstruction in view of PROBA2 Margit Haberreiter, PMOD/WRC, Davos, Switzerland Cis Verbeeck, Veronique Delouille, Rami Qahwaji ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter 1

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3. Absorption of EUV in the Earth‘s atmosphere Altitude-wavelength dependence of energy deposition from solar irradiance units of Log 10 (Wm -4 ) From Solomon and Qian 2005 Solar minimum conditions EUV varies by a factor of 2 and more!!

4. Global Mean Neutral Density vs F10.7 ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter Long-term variation due to solar forcing (here F10.7) Short-term variations visible in geomagnetic variations (Ap index) 4

5. Neutral Density versus EUV irradiance 5 ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter

6. Modeling the Solar EUV Spectrum Wavelengths – UV: 120 – 400 nm –EUV: 10 – 120 nm Contribution from the –Chromophere –Transition region –Corona

7. I(λ,μ,φ,t) n level, n el,n ion,… (x,y,z,t) I(λ,μ,φ,t) Iterative process EUV reconstruction - Semi-empirical modeling ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter 7

8. Comparison to SDO/EVE observations Haberreiter, 2011, Solar Physics, 274, 473 ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter 8

9. Synthetic EUV Spectra Quiet Corona Quiet Coronal Network Active Coronal Network Hot loops Super hot loops ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter 9

10. EIT Image Decomposition June 1, 2003 Coronal Hole MaskActive Region Mask SPoCA Image Decomposition: Cis Verbeeck, ROB ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter 10

11. Area coverage over solar cycle 23 Data from Barra et al, 2009Barra et al., 2009, A&A ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter 11

12. ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter Reconstruction of the EUV for solar cycle 23 Haberreiter, 2012, IAU Symposium 286 12

13. SWAP integrated intensities ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter Mean of off-limb contribution:  35% 13

14. Reconstruction of the EUV for solar cycle 23 ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter 14

15. FP7 Space Project SOLID SOLID: First European Comprehensive SOLar Irradiance Data exploitation Coordinator PMOD/WRC (W. Schmutz, Project Manager: M. Haberreiter) Start: December 2012 10 Partners from 7 European Countries (CH, F, B, UK, D, EL, I) Compilation and Analysis of the existing irradiance observations from the XUV/EUV, UV, visible to the IR along with the state-of-the-art irradiance modelling results ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter 15

16. Conclusion ESWW9, Brussels, Nov 4-7 2012 Margit Haberreiter Understanding the physical mechanisms that drive solar spectral irradiance variations is important for Space Weather studies Successful reconstruction based on EIT image analysis Improvement of implementation of extended corona Extend the reconstruction to PROBA2 time series based on SWAP decomposition More to come soon within the FP7 SOLID project 16