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Version 2 NSF network data:
Model Implementation
Model calculations that are part of Version 2 were performed with the radiative transfer model
UVSPEC/libRadtran. These calculations serve the following purposes:
- Retrieval of total column ozone
- Determination of the contribution of the Sun's direct beam to global irradiance, which is an important parameter for the cosine error correction
- Calculation of "flags"
- Quality control of Version 2 spectra
Plots showing a comparison of measured and modeled spectra are provided for each spectrum that is part of Version 2. The following annotated examples give an overview of the information that can be gained from such comparison:
- CB940600-351a.pdf: Clear-sky spectrum
- CB940800-349a.pdf: Cloudy-sky spectrum
No "Cloud model" values are given for wavelengths below 340 nm, as total ozone is not an input parameter for the cloud model. "Cloud model" spectra also do not take the sphericity of the Earth into account; spectra for solar zenith angles larger than 75 degrees may therefore underestimate the true spectrum significantly.
Discrepancies between measured and modeled spectra, which may be apparent in these plots, can be caused by the way the atmosphere is described by the model. By comparing measured and modeled spectra, deficiencies in the description of the atmosphere by the model can be uncovered, leading to a better understanding of the processes affecting the transfer of radiation through the atmosphere.
A more detailed description of the model implementation is in preparation.
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