Assessment of scatterometer data for environmental studies in Thar desert

Since summer 1991 the scatterometer aboard European Remote Sensing Satellites ERS-1 and ERS-2 have provided global radar backscatter measurements of the Earth's surface. Over the oceans, these data are used operationally for wind field retrieval. Simultaneously possible applications of these low resolution data over land surfaces were studied by numerous investigators. Due to the global coverage, the continuity of the data and the wide range of incidence angle these data have been found to provide valuable information despite the coarse resolution. The authors analyze normalized radar cross section (NRCS) measurement obtained over Thar desert in Pakistan between May 1994 and May 1996. Spatial variations in the radar cross section are compared with vegetational and meteorological parameters. Seasonal as well as interannual variations are investigated by correlating the radar backscatter with phenological, meteorological and AVHRR NDVI data. Zonal characterization of area is made on the basis of backscatter behavior and meteorological data. The geophysical parameters of the land are reflected in the incidence angle diversity of the ERS scatterometer. It is demonstrated that valuable information can be delineated from the ERS scatterometer data over arid regions in order to provide data for environmental and especially climatic monitoring.