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Accomplishments

Intercomparison of sea ice broadband albedo parameterizations.
Regional and global climate models use a variety of parameterization schemes to represent the surface shortwave albedo of sea ice. Visible and near-infrared albedos were derived from the SHEBA broadband and spectral albedo measurements using radiation transfer modeling constrained with AVHRR/CASPR-derived water vapor amount and cloud properties (Key, 2002). We have shown that the best parameterization under review reproduced the summer sea ice broadband, visible and near-infrared albedos with the root mean square error (RMSE) of 6%, 6.8% and 5%, accordingly (Figure 1). Advanced parameterization of sea ice albedo, explicitly dependent on the melt pond area fraction and depth, gave better results, with RMSE of 2%, 2.5% and 1.4%, correspondingly. Figure 1 shows the results of the parameterization intercomparison. Published parameterizations of sea ice broadband, visible and near-infrared albedos composed of five schemes for snow fraction, four schemes for snow-covered ice albedo and four schemes for snow-free ice albedo dependent on surface air temperature and snow depth were intercompared using SHEBA in situ data (Uttal, 2002).

figure 1

Figure 1. Intercomparison of the advanced broadband sea ice albedo parameterization among other published parameterizations on SHEBA data. Error means and standard deviations for each parameterization (enclosed in brackets) are indicated inside the legend bar.

References

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