Modeling the UV/EUV for the Current Solar Minimum and Beyond
Margit Haberreiter [Margit.Haberreiter@lasp.colorado.edu], Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder
Solar spectral irradiance variations in the UV/EUV are important for the detailed modeling of the Earth's ionosphere. We present realistic synthetic spectra for this wavelength range. Our approach involves two main steps. First, we calculate the optically thick radiation based on time-independent 1D atmosphere structures for different activity features of the chromosphere and transition region. Second, we use 1D coronal atmosphere structures representing various activity features to calculate the optically thin coronal spectrum. In order to account for the spatial extension of the corona, we employ a spherical integration scheme for the calculation of the coronal spectrum. The temporal variability of the spectrum is determined from the analysis of SOHO/EIT images. The current state of this analysis as well as the calculated spectra will be presented. Comparisons of the synthetic spectra with available observations such as the EVE calibration spectrum obtained during a rocket flight on April 14, 2008, as well as other data from SORCE/XPS, and TIMED/SEE, and SOHO/EIT will be presented.