Abstract:
This paper reports the development of a soil moisture
retrieval algorithm for spaceborne passive microwave
radiometers. The algorithm is based on a modified radiative
transfer model, so-called DMRT-AIEM model. The
implementation of this algorithm consists of three steps: 1)
forward model parameters optimization; 2) lookup table
generation and 3) lookup table reversion and soil moisture
estimation. The algorithm was tested at a CEOP (Coordinate
Enhanced Observing Period) reference site on the Mongolia Gobi.
The retrieved soil moisture data was compared with the in situ
observations. The comparison results show that the performance
of the new algorithm is good, giving a Standard Error of the
Estimate (SEE) of 3.8% and R-square of 0.4. Moreover, a
successful TB validation on SSM/I low frequencies was achieved
by the RTM used in this algorithm. It means this algorithm
provides a possibility to retrieval around 20 years’ soil moisture
data from SSM/I observations.