Pn. Pathak et al., LARGE-AREA SOIL-MOISTURE ESTIMATION USING INSAT-VHRR INFRARED DATA, Indian journal of radio & space physics, 22(3), 1993, pp. 156-164
It has been shown by earlier workers that rate of change of land surfa
ce temperature (DELTAT) during mid-morning hours as determined from th
e thermal infrared sensor onboard geosynchronous satellite can provide
a good signature of area-averaged soil moisture. In order to examine
the feasibility of this approach, a pilot study was undertaken using l
imited data of INSAT-VHRR. Since no concurrent measurements of soil mo
isture and other meteorological data were available, the analysis was
carried out making a number of simplifying assumptions. The observed D
ELTAT during April 1991 showed a reasonably good association with arid
and semi-arid regions of Rajasthan and Gujarat, respectively, while D
ELTAT during September 1991 was found to be negatively correlated with
the area-averaged total rainfall data over Gujarat. Although these re
sults are encouraging, they can at best be considered as indicative of
physical processes in view of the simplifying assumptions. More rigor
ous analysis is essential to establish the validity of the approach.