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

Davis, C. J. ORCID: https://orcid.org/0000-0001-6411-5649, Clarke, E. M., Bamford, R. A., Lockwood, M. ORCID: https://orcid.org/0000-0002-7397-2172 and Bell, S. A. (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. Annales Geophysicae, 19 (3). pp. 263-273. ISSN 0992-7689 doi: 10.5194/angeo-19-263-2001

Abstract/Summary

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, phi, 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 phi has a negligible probability of being a chance occurrence.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/38724
Identification Number/DOI	10.5194/angeo-19-263-2001
Refereed	Yes
Divisions	No Reading authors. Back catalogue items Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Copernicus Publications
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