Evaluating soil moisture retrieved from a portable L-band radiometer

Soil moisture (SM) is an essential climate variable for regulating water and energy balances at land-atmosphere interactions influencing the growth of plants and other living organisms. L-band ground-based portable microwave radiometers (1.4 GHz) is considered a viable technology to monitor the top few centimeters of SM. For the present study, a passive ground-based portable L-band microwave radiometer was deployed to measure horizontally and vertically polarized microwave brightness temperature (TB). The TB observations were then used to retrieve the SM with validation using in-situ observed SM. The variation of TB and SM with two different soil types was also evaluated to examine the dependence of soil texture in SM retrieval. The measurement results demonstrated significant spatial variability in brightness temperature (TB) with respect to varying soil moisture (SM). Horizontally (H) polarized TB was found to be more sensitive than Vertically (V) polarized TB. On the other hand, the sensitivity of V-polarization is more significant on bare soil with grass. H-polarized SM performs better than V-polarized SM on all the soil types with less bias and RMSE. Also, validation findings reveal RMSE values smaller than 0.04 m3 m-3, target accuracy achieved by satellite mission for SM retrieval. (c) 2024 COSPAR. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.