ACP Atmospheric Chemistry and Physics ACP Atmos. Chem. Phys. 1680-7324 Copernicus Publications Göttingen, Germany 10.5194/acp-8-2965-2008 Reconstruction of the solar spectral UV irradiance for nowcasting of the middle atmosphere state on the basis of LYRA measurements Egorova T. 1 Rozanov E. 1 2 Hochedez J.-F. 3 Schmutz W. 1 Physikalisch-Meteorologisches Observatorium Davos and World Radiation Center, Dorfstrasse 33, 7260 Davos Dorf, Switzerland Institute for Atmospheric and Climate Science, ETH Zürich, Universitätsstr. 16, 8092 Zürich, Switzerland Royal Observatory of Belgium, Circular Avenue 3, 1180 Brussels, Belgium 12 06 2008 8 11 2965 2973 Copyright: © 2008 T. Egorova et al. 2008 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://acp.copernicus.org/articles/8/2965/2008/acp-8-2965-2008.html The full text article is available as a PDF file from https://acp.copernicus.org/articles/8/2965/2008/acp-8-2965-2008.pdf

The LYRA instrument onboard ESA PROBA2 satellite will provide 6-hourly solar irradiance at the Lyman-alpha (121.6 nm) and the Herzberg continuum (~200–220 nm wavelength range). Because the nowcasting of the neutral and ionic state of the middle atmosphere requires the solar irradiance for the wide spectral range (120–680 nm) we have developed the statistical tool for the reconstruction of the full spectrum from the LYRA measurements. The accuracy of the reconstructed irradiance has been evaluated with 1-D transient radiative-convective model with neutral and ion chemistry using the daily solar spectral irradiance measured with SUSIM and SOLSTICE instruments onboard UARS satellite. We compared the results of transient 1-year long model simulations for 2000 driven by the observed and reconstructed solar irradiance and showed that the reconstruction of the full spectrum using linear regression equation based on the solar irradiance in two LYRA channels can be successfully used for nowcasting of the middle atmosphere. We have also identified conditions when the proposed approach does not yield spectral reconstruction with sufficient accuracy.

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