Airborne and Spaceborne Passive Microwave Measurements of Soil Moisture

Abstract

Soil moisture is the key variable that controls the surface water movements including infiltration, evapotranspiration, and groundwater recharge. It is one of the most important surface conditions of the exchange processes between land and atmosphere. Microwave remote sensing provides an efficient way to map surface soil moisture at a large scale from space and has achieved rapid development especially in large aperture systems at L-band. This chapter describes the basic theory and methodology for retrieving surface soil moisture including the soil roughness and vegetation effects. Special cases of soil moisture estimates from airborne and spaceborne measurements are presented. Results demonstrated that multichannel (multi-angle or multifrequency) microwave observations can be combined to enhance the retrieval accuracy and spatial resolution of remote sensed soil moisture.