Effects of Satellite Spectral Resolution and Atmospheric Water Vapor on Retrieval of Near-Ground Temperatures.

摘要

One of the challenges in remote sensing of surface temperatures for meteorological applications is to distinguish clearly the influence of the ground surface on the measured radiances from the influence of the overlaying atmosphere. It is common, particularly in cloud-free situations, to have large differences in temperature over very short vertical distances from the ground up through the lowest kilometer of the atmosphere. The research to be presented focused on the vertical resolution capabilities of the VISSR Atmospheric Sounder (VAS) and the proposed GOES High-Resolution Interferometer Sounder (GHIS) in this lowest part of the temperature profile. Results of simulated retrievals and experiments on the sensitivity of radiances to profile perturbations indicated that, for a moderately moist atmosphere, ground surface temperature errors of about 1 deg C and low-level air temperature errors of about 3 deg C can occur in VAS retrievals due specifically to vertical resolution limitations and instrument noise. For a drier atmosphere the surface temperature errors tend to be smaller and the low-level air temperature errors tend to be larger. These values do not account for other sources of retrieval error, such as interference by clouds, uncertainty of the ground surface emittance, or deficiencies in the radiative transfer computation method.