Eclipses observed by LYRA - a sensitive tool to test the models for the solar irradiance
arXiv:1201.6546 · doi:10.1007/s11207-012-0063-0
Abstract
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.
19 pages, 9 figures, Solar Physics
References in corpus (8)
- Evolution of the solar irradiance during the Holocene
- A new approach to long-term reconstruction of the solar irradiance leads to large historical solar forcing
- Center-to-Limb Variation of Solar 3-D Hydrodynamical Simulations
- NLTE solar irradiance modeling with the COSI code
- Why one-dimensional models fail in the diagnosis of average spectra from inhomogeneous stellar atmospheres
- NLTE model calculations for the solar atmosphere with an iterative treatment of opacity distribution functions
- The LYRA Instrument Onboard PROBA2: Description and In-Flight Performance
- NLTE modeling of Stokes vector center-to-limb variations in the CN violet system
Cited by in corpus (4)
- Recent variability of the solar spectral irradiance and its impact on climate modelling
- The LYRA Instrument Onboard PROBA2: Description and In-Flight Performance
- The role of the Fraunhofer lines in solar brightness variability
- Detection of Solar Rotational Variability in the LYRA 190 - 222 nm Spectral Band