Reconstruction of the solar EUV irradiance from 1996 to 2010 based on SOHO/EIT images
Physikalisch-Meteorologisches Observatorium and World Radiation Center, Dorfstrasse 33, CH-7260
Davos Dorf, Switzerland
2 STCE/Royal Observatory of Belgium, Avenue Circulaire 3, 1180 Brussels, Belgium
3 DAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, UK
4 University of Southern California Space Sciences Center, 835 Bloom Walk, Los Angeles, CA 90089, USA
* Corresponding author: email@example.com
Accepted: 28 August 2014
The solar Extreme UltraViolet (EUV) spectrum has important effects on the Earth’s upper atmosphere. For a detailed investigation of these effects it is important to have a consistent data series of the EUV spectral irradiance available. We present a reconstruction of the solar EUV irradiance based on SOHO/EIT images, along with synthetic spectra calculated using different coronal features which represent the brightness variation of the solar atmosphere. The EIT images are segmented with the SPoCA2 tool which separates the features based on a fixed brightness classification scheme. With the SOLMOD code we then calculate intensity spectra for the 10–100 nm wavelength range and each of the coronal features. Weighting the intensity spectra with the area covered by each of the features yields the temporal variation of the EUV spectrum. The reconstructed spectrum is then validated against the spectral irradiance as observed with SOHO/SEM. Our approach leads to good agreement between the reconstructed and the observed spectral irradiance. This study is an important step toward understanding variations in the solar EUV spectrum and ultimately its effect on the Earth’s upper atmosphere.
Key words: Corona / Sun / Solar cycle / Spectral irradiance / Space Weather
© M. Haberreiter et al., Published by EDP Sciences 2014
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.