Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.621 IF 1.621
  • IF 5-year value: 1.614 IF 5-year
    1.614
  • CiteScore value: 1.61 CiteScore
    1.61
  • SNIP value: 0.900 SNIP 0.900
  • SJR value: 0.910 SJR 0.910
  • IPP value: 1.58 IPP 1.58
  • h5-index value: 24 h5-index 24
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 80 Scimago H
    index 80
Volume 19, issue 3
Ann. Geophys., 19, 263-273, 2001
https://doi.org/10.5194/angeo-19-263-2001
© Author(s) 2001. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 19, 263-273, 2001
https://doi.org/10.5194/angeo-19-263-2001
© Author(s) 2001. This work is distributed under
the Creative Commons Attribution 3.0 License.

  31 Mar 2001

31 Mar 2001

Long term changes in EUV and X-ray emissions from the solar corona and chromosphere as measured by the response of the Earth’s ionosphere during total solar eclipses from 1932 to 1999

C. J. Davis1, E. M. Clarke2, R. A. Bamford1, M. Lockwood3, and S. A. Bell4 C. J. Davis et al.
  • 1Rutherford Appleton Laboratory, Chilton, Oxfordshire, UK
  • 2Sheffield Hallam University, Sheffield, Yorkshire, UK
  • 3Department of Physics and Astronomy, Southampton University, Southampton, UK
  • 4HM Nautical Almanac Office, Rutherford Appleton Laboratory, Chilton, Oxfordshire, UK
  • Correspondence to: C. J. Davis (c.j.davis@rl.ac.uk)

Abstract. Measurements of the ionospheric E region during total solar eclipses in the period 1932–1999 have been used to investigate the fraction of Extreme Ultra Violet and soft X-ray radiation, 8, that is emitted from the limb corona and chromosphere. The relative apparent sizes of the Moon and the Sun are different for each eclipse, and techniques are presented which correct the measurements and, therefore, allow direct comparisons between different eclipses. The results show that the fraction of ionising radiation emitted by the limb corona has a clear solar cycle variation and that the underlying trend shows this fraction has been increasing since 1932. Data from the SOHO spacecraft are used to study the effects of short-term variability and it is shown that the observed long-term rise in 8 has a negligible probability of being a chance occurrence.

Key words. Ionosphere (solar radiation and cosmic ray effects) – Solar physics, astrophysics, and astronomy (corona and transition region)

Publications Copernicus
Download
Citation
Share