| MICRO-SWEAT, a physically based soil water
and energy balance model coupled with a microwave emission model, was used to
investigate the relationship between near surface soil moisture (θ0-5) and
L-band microwave brightness temperature (TB) under a wide range of
conditions. The effects of soil texture, look angle and vegetation on this
relationship were parameterised and combined into a simple summary model
relating θ0-5 to TB. This model retains much of the physical basis of
MICRO-SWEAT but can be used in more data limiting circumstances. It was tested
using a variety of truck-based L-band data sets collected between 1980 and 1982.
This paper emphasises the need to have an accurate estimate of the vegetation
optical depth (a parameter that describes the degree of influence of the
vegetation on the microwave emission from the soil surface) in order to retrieve
correctly the soil water content.
Keywords: passive microwave, soil moisture, remote sensing, vegetation,
retrieval algorithm |