ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-7-5775-2007 Effects of total solar eclipse of 29 March 2006 on surface radiation Kazadzis S. 1 Bais A. 1 Blumthaler M. 2 Webb A. 3 Kouremeti N. 1 Kift R. 3 Schallhart B. 2 Kazantzidis A. 1 Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Greece Division of Biomedical Physics, Innsbruck Medical University, Austria School of Earth Atmospheric and Environmental Sciences, University of Manchester, UK 22 11 2007 7 22 5775 5783 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/7/5775/2007/acp-7-5775-2007.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/7/5775/2007/acp-7-5775-2007.pdf

Solar irradiance spectral measurements were performed during a total solar eclipse. The spectral effect of the limb darkening to the global, direct irradiance and actinic flux measurements was investigated. This effect leads to wavelength dependent changes in the measured solar spectra showing a much more pronounced decrease in the radiation at the lower wavelengths. Radiative transfer model results were used for the computation of a correction for the total ozone measurements due to the limb darkening. This correction was found too small to explain the large decrease in total ozone column derived from the standard Brewer measurements, which is an artifact in the measured irradiance due to the increasing contribution of diffuse radiation against the decreasing direct irradiance caused by the eclipse. Calculations of the Extraterrestrial spectrum and the effective sun's temperatures, as measured from ground based direct irradiance measurements, showed an artificial change in the calculations of both quantities due to the fact that radiation coming from the visible part of the sun during the eclipse phases differs from the black body radiation described by the Planck's law.

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