A. I. Shapiro, 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
PROBA-2. 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. It hence can be used as a reliable tool for modeling the
variability of the spectral solar irradiance.
View original:
http://arxiv.org/abs/1201.6546
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