An Air-to-Soil Transition Model for Discrete Scattering–Emission Modelling of L-Band Radiometry at Maqu site, the Eastern Tibetan Plateau

In situ ELBARA-III radiometer observations of brightness temperature T_B^p (with p = H, V) in Maqu site, the eastern Tibetan Plateau were used for investigations on roughness effects over natural land surface and on coherent and incoherent emission processes in radiative transfer modelling. Aided by in situ soil moisture (SM) and temperature profile measurments and the MCD15A2H - MODIS/Terra+Aqua Leaf Area Index, the study simulated T_B^p and demonstrated a necessity of an air-to-soil transition (AS) model in incorporating roughness effects for understanding seasonal L-band radiometry. Supported by the in situ meteorological observation data in Maqu site, the applicability and uncertainty of AS-based models in T_B^p simulations were discussed. The meteorological data involve precipitation intensity, air temperature, and albedo with ground temperature, which were derived from the in situ four components radiation measurement (i.e., up- and down-welling shortwave and longwave radiations).