Estimation of surface soil moisture in a semi-arid, mountainous region using satellite microwave observations : a case study of southwestern region of Saudi Arabia

الملخص EN

This study presents the use of passive microwaves to classify and estimate the surface soil moisture in a semi-arid, mountainou s regio n.

The southweste rn regio n of Saud i Arabia was chosen for this study.

Two case studies have been considered to investigate the response of Special Sensor Microwave/Imager (SSM/I) brightn ess temperature to soil moisture .

The first case is at satellite ascending overpass time (about 6:00 a.m.

local solar time) .

and the seco nd one is at satellite descend ing overpass time (about 6:00 p.m.

local solar time).

It is shown that normalized brightne ss temp er ature with respect to ground temp er ature may be interpreted in term s of the soil moisture in the surface layers.

Normalized brightn ess temper ature is not sensitive to soil moisture when precipitating cloud s are presen t.

The existence of precipitating clouds over the study area was determined through examination of the brightn ess temp er ature of frequ en cy 85.5 GHZ(Gigah ert z).