85th AMS Annual Meeting

Thursday, 13 January 2005
MODIS Albedo Data in Greenland Ice Sheet Climate Modeling: Melt Sensitivity, Climate Feedback, and Assimilation Development
Jason Box, Byrd Polar Research Center, Columbus, OH; and J. C. Stroeve and A. W. Nolin
Surface albedo is among the most crucial parameters in the surface energy budget for seasonally melting ice surfaces. Evolving albedo parameterizations are attractive for use when observations are unavailable. However, satellite-derived surface albedo estimates facilitate direct data assimilation for climate hindcasts. Thus, MODIS radiances are converted to surface albedo invoking polar-specific algorithms for cloud detection, atmospheric correction, and viewing and reflectance geometric effects. The MODIS albedo results are compared with in-situ observed albedo, the standard MODSI albedo product, and various evolving albedo parameterizations. Available normalized viewing geometry MODIS albedo data are assimilated into Polar MM5 regional climate model simulations of Greenland ice sheet surface melting. Modeled surface climate under different albedo configurations are compared to assess melt sensitivity and climate feedback in the atmospheric model to the various albedo data. In the process, a tailored ice sheet MODIS albedo product is produced for future melt modeling and near-real-time melt monitoring. Indirectly, MODIS cloud detection is evaluated over the ice sheet. Further, meltwater production estimates for various drainage basins and for the ice sheet as a whole are more precisely derived.

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