Land data assimilation with satellite measurements for the estimation of surface energy balance components and surface control on evaporation

A variational land data assimilation system is used to estimate latent heat flux and surface control on evaporation. The dynamic equation for surface temperature with energy balance is used as a constraint on the estimation u sing the adjoint technique. Measurements of land surface temperature from s atellite remote sensing are assimilated over two subregions within the Sout hern Great Plains 1997 hydrology field experiment. The performance of the e stimation is linked to the timing of the satellite overpass. During days wh en the measurements close to the time of peak ground temperature are availa ble, the estimation is adequate. The approach shows that satellite remote s ensing of land temperature may be used to provide estimates of components o f the surface energy balance and land surface control on evaporation. The l atter parameter is related to surface soil moisture, and here they are comp ared with independent values derived from ground measurements.