Remote sensing of soil-vegetation- atmosphere transfer processes

This article assesses the potentially powerful combination of remotely sensed data and soil-vegetation-atmosphere transfer (SVAT) schemes. SVATS represent the hydrological processes occurring at the land surface and can be used to estimate, among other processes, the exchange of water and energy between the soil, vegetation and the atmosphere. They require information about the interaction of radiation with the soil and vegetation. Bidirectional reflectance models are now starting to be used to determine the partitioning of radiation. An example of the combination of a simple geometric optics model of bidirectional reflectance and computer graphics is given, where simulations of remotely sensed scenes are produced. The next step is to couple these models to a SVAT scheme. The output of a SVAT scheme can also be used to drive radiative transfer models at different wavebands. This approach is illustrated by the estimation of soil hydraulic properties using a time series of passive microwave emission observations.