Extraction of Surface Temperature from Satellite Data

Abstract

The surface temperature figures in nearly all equations for energy fluxes through a surface element. It is routinely derived from satellite radiances over the oceans. However, over land the changing surface emissivity, strong daytime heating as well as nighttime cooling and the difficulty of defining surface temperature for a canopy, have prevented a routine application. This paper shows the possible influences of water vapour content, near surface thermal structure, aerosol particles, thin clouds, slant paths and surface emissivity on the correction of atmospheric masking. A procedure for land surface temperature determination for the NOAA 7, 9 satellite data comprising four steps is put forward:

• water surface temperature derivation;

• interpolation of the water surface correction;

• additional correction due to heated or cooled surfaces;

• choice of the highest temperature from the three thermal IR channels.

The procedure is applied to a daytime and a nighttime scene covering the Alps.