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 (theta (0-5)) and L-band microwave brigh
tness temperature (T-B) under a wide range of conditions. The effects of so
il texture, look angle and vegetation on this relationship were parameteris
ed and combined into a simple summary model relating theta (0-5) to T-B. Th
is 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 emphasi
ses 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 t
he soil water content.