A Ten-Year (1993-2002) Time-Series of Microwave Land Emissivity

摘要

A new algorithm is developed to retrieve the land surface emissivity at four SSM/I frequencies. The coefficients used in the algorithm are directly derived from a training data set including land emissivity and SSM/I measured brightness temperatures. The training data set is also derived from SSM/I brightness temperatures by removing the effects of atmospheric emission and surface temperature. In doing so, the upwelling and downwelling brightness temperature as well as atmospheric transmittance are computed directly from the global data assimilation system (GDAS) temperature and moisture profiles, and surface temperature. Global monthly mean emissivity maps are generated from the daily products. The retrievals under rain regions are not used in the averaging. The rainy pixels were screened out using SSM/I precipitation algorithm.