Submitted to: American Geophysical Union
Publication Type: Proceedings
Publication Acceptance Date: 10/1/1998
Publication Date: N/A
Interpretive Summary: This paper assesses the possibility of using repetitive observation of remotely sensed surface soil moisture to estimate soil hydraulic properties.
Technical Abstract: Remote sensing makes use of electromagnetic energy that is reflected or emitted from the land surface to make observations of the surface. These include reflected solar energy, e.g., with Landsat, reflected microwave energy, i.e., imaging radars, emitted thermal radiation in the infrared for surface temperatures and in the microwave for surface soil moisture. These observations are primarily of the surface layer with the microwave sensors yielding information about a surface layer of at most 5 cm, thick. Thus, no remote sensing technique directly yields information on the vadose zone. To obtain information about this zone we must use models to relate the remotely sensed observations to subsurface parameters. This is best done with models which couple the surface layer observations to the subsurface properties. In general, this will require repetitive measurements so that the model predictions of temporal variation can be compared to the data. The model parameters can then be adjusted to yield better agreement. Several examples of estimating soil hydraulic properties from a time series of microwave radiometric observations of surface soil moisture are presented. The results showed good agreement with classical measurements of these properties.