Comparison of SMOS soil moisture/brightness temperatures for morning and evening passes

Abstract

Soil moisture is an essential element, which controls the land-atmospheric system and thus, its continuous monitoring is extremely important. Regular monitoring of spatio-temporal variability of surface soil moisture can be done using microwave remote sensing techniques, as there is high contrast in dielectric properties of pure dry soil (2-3) and pure water (80) at microwave frequencies. Variation in surface soil moisture is not only affected by precipitation, evaporation and transpiration, but often groundwater and root zone moisture also play an important role. In the present paper, surface soil moisture data from Soil Moisture and Ocean Salinity (SMOS) satellite is used to analyse the changes in surface soil moisture from evening to next or following morning (6.00 PM and 6.00 AM) in an arid region of Rajasthan, India. An increase in surface soil moisture is observed for maximum data from evening to following morning. The same trends were also verified using polarization index values.