Comparison of Evaporation Estimated by Satellite Remote Sensing With Estimates From a Land Surface Model

Evaporation provides the link between the energy and water budgets at the land surface. Accurate measurements of evaporation rates at large spatial scales are central to understanding the feedback mechanisms between the land and atmosphere. However, with the paucity of available surface observations for many portions of the globe, the use of modeled evaporation using satellite-based remotely sensed inputs is a potentially viable surrogate. Estimates of evaporation are made using two conceptually different models. The Surface Energy Balance System (SEBS) estimates atmospheric turbulent heat fluxes and evaporative fraction using satellite derived surface temperature and near-surface meteorological variables, usually from standard surface stations. The Variable Infiltration Capacity (VIC) model solves the land surface water and energy balances at scales from the point up to several 100km using standard radiative and meteorological inputs. A common set of land surface data, including vegetation type distribution and related parameters such as LAI and albedo, are used to specify the land surface in each model. Comparison of estimated evaporation from the two models is made over the Oklahoma region of the USA for a 2 month warm season period.