Ideal brightness temperature algorithm for estimating soil-profile water status: I. Algorithm development

One of the present efforts in the field of microwave remote sensing is to estimate soil water status throughout the soil profile using radiometers. This study describes a simple, ideal algorithm relating microwave brightness temperature (TB) and soil water status in the upper (10 cm) and lower (greater than 10 cm) soil depths. The algorithm description considers a simple, homogeneous, and sandy soil system with negligible amounts of capillary-stored water, organic matter content, and surface roughness. The microwave TB was estimated from the dielectric constant, k, as a function of the amount of water remaining in the soil during drainage. The effect of downward fluxing, free water on the value of TB was greater and occurred over a shorter period than that of the slower draining water near field capacity. The predictability of the algorithm decreased as the moisture content decreased to that of approximately field capacity.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.