On the Use of Satellite Data to Infer Surface Fluxes at Meteorological Scales

For numerical meteorological prediction, the determination of energy, momentum and moisture fluxes at the earth's surface requires knowledge of surface properties at a very coarse spatial resolution. A procedure is described for estimating the important surface properties (diurnal heat capacity, moisture availability) through analysis of high spatial resolution visible and thermal infrared data from satellites. An averaging method is then specified for aggregating or parameterizing local estimates of surface properties to a relatively coarse grid spacing. The method considers grid scale fluxes between ground and atmosphere, specifying that parameterized surface values should yield fluxes equal to those produced by integration of the high spatial resolution description of the surface. This allows estimation of latent and sensible heat exchange with the atmosphere at the large scales of general circulation models. The procedure is illustrated by application to a data set from the Heat Capacity Mapping Mission.