Articles | Volume 26, issue 2
Ann. Geophys., 26, 269–279, 2008

Special issue: 3rd European Space Weather Week (ESWW)

Ann. Geophys., 26, 269–279, 2008

  26 Feb 2008

26 Feb 2008

Review on the solar spectral variability in the EUV for space weather purposes

J. Lilensten1, T. Dudok de Wit2, M. Kretzschmar3, P.-O. Amblard4, S. Moussaoui5, J. Aboudarham6, and F. Auchère7 J. Lilensten et al.
  • 1LPG, CNRS and Joseph Fourier University, Bâtiment D de Physique, BP 53, 38041 Saint-Martin d'Hères cedex 9, France
  • 2LPCE, CNRS and University of Orléans, 3A avenue de la Recherche Scientifique, 45071 Orléans cedex 2, France
  • 3SIDC, Royal Observattory of Belgium, avenue circulaire 3, 1180 Brussels, Belgium
  • 4GIPSAlab, CNRS, 961 Rue de la Houille Blanche, BP 46, 38402 St. Martin d'Hères cedex, France
  • 5IRCCYN, 1, rue de la Noë, BP 92101, 44321 NANTES Cedex 3, France
  • 6LESIA, Paris Observatory, 5 Place Jules Janssen, 92195 Meudon, France
  • 7IAS, CNRS and Paris-Sud University, Bâtiment 121, 92405 Orsay cedex, France

Abstract. The solar XUV-EUV flux is the main energy source in the terrestrial diurnal thermosphere: it produces ionization, dissociation, excitation and heating. Accurate knowledge of this flux is of prime importance for space weather. We first list the space weather applications that require nowcasting and forecasting of the solar XUV-EUV flux. We then review present models and discuss how they account for the variability of the solar spectrum. We show why the measurement of the full spectrum is difficult, and why it is illusory to retrieve it from its atmospheric effects. We then address the problem of determining a set of observations that are adapted for space weather purposes, in the frame of ionospheric studies. Finally, we review the existing and future space experiments that are devoted to the observation of the solar XUV-EUV spectrum.