Simulation of Passive Microwave Data Toward Efficient Assimilation Over Indian Subcontinent

Brightness temperature (Tb) is sensitive to soil moisture (SM) estimates and has the advantage of increasing the spatial coverage of SM measurements. This letter focuses on the simulation of Tb from the land surface variables generated by Noah with multiparameterized (Noah-MP) and a forward observation operator, community microwave emission model (CMEM) over the Indian subcontinent with a spatial resolution of 0.25
^°
×0.25
^°
. Traditionally, soil dielectric constant and vegetation optical depth are the most important parameters that affect the sensitivity of the top of the atmosphere Tb. Hence, the results of the simulated Tb are presented for a total of 12 configurations and the one with better result (C12) is compared against the microwave polarization difference index (MPDI)-based Tb and observed SM and ocean salinity (SMOS) Tb. The simulated SM from the land surface model (LSM) is also compared with the observed SMOS SM to examine the sensitivity of the simulated Tb with SM. The results reveal that MPDI approach has immense potential in simulating the observed Tb and can be used toward the development of an efficient Tb assimilation system.