Solar Physics

, Volume 286, Issue 1, pp 271–287 | Cite as

Eclipses Observed by Large Yield RAdiometer (LYRA) – A Sensitive Tool to Test Models for the Solar Irradiance

  • A. I. ShapiroEmail author
  • W. Schmutz
  • M. Dominique
  • A. V. Shapiro


We analyze the light curves of the recent solar eclipses measured by the Herzberg channel (200 – 220 nm) of the Large Yield RAdiometer (LYRA) onboard Project for OnBoard Autonomy (PROBA2). The measurements allow us to accurately retrieve the center-to-limb variations (CLV) of the solar brightness. The formation height of the radiation depends on the observing angle, so the examination of the CLV provide information about a broad range of heights in the solar atmosphere. We employ the 1D NLTE radiative transfer COde for Solar Irradiance (COSI) to model the measured light curves and corresponding CLV dependencies. The modeling is used to test and constrain the existing 1D models of the solar atmosphere, e.g. the temperature structure of the photosphere and the treatment of the pseudo-continuum opacities in the Herzberg continuum range. We show that COSI can accurately reproduce not only the irradiance from the entire solar disk, but also the measured CLV. Hence it can be used as a reliable tool for modeling the variability of the spectral solar irradiance.


Solar Irradiance Solar Atmosphere Solar Eclipse Contribution Function Solar Brightness 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The research leading to this article was supported by the Swiss National Science Foundation under grant CRSI122-130642 (FUPSOL) and grant 200020-130102. We thank the PROBA2/LYRA science team for their work in producing the data sets used in this article and their helpful recommendations. LYRA is a project of the Centre Spatial de Liège, the Physikalisch-Meteorologisches Observatorium Davos, and the Royal Observatory of Belgium funded by the Belgian Federal Science Policy Office (BELSPO) and by the Swiss Bundesamt für Bildung und Wissenschaft. PROBA2 is an ESA micro satellite operated by the Director for Science and Robotic Exploration.


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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • A. I. Shapiro
    • 1
    Email author
  • W. Schmutz
    • 1
  • M. Dominique
    • 2
  • A. V. Shapiro
    • 1
  1. 1.Physikalisch-Meteorologishes Observatorium DavosWorld Radiation CenterDavos DorfSwitzerland
  2. 2.Royal Observatory of BelgiumBrusselBelgium

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