Impact of surface roughness, vegetation opacity and soil permittivity on L-band microwave emission and soil moisture retrieval in the third pole environment

For the Tibetan meadow site, the τ-ω emission model overestimates both TBH and TBV during the warm season and underestimates TBH during the cold season when the vegetation is sparse. Implementation of the new surface roughness parameterization reduces the TBH underestimation, and further the TBp overestimation is mitigated by adopting a new τp parameterization derived from a discrete radiative transfer model previously developed and tested for the same site. The in-situ measured θliq dynamics are better captured by corresponding retrievals for both frozen and thawed soils with implementation of the new surface roughness and τp parameterizations, which reduces the unbiased RMSEs by more than 40%. The parameterizations developed in this study are useful to provide consistent and reasonable TBp simulations and θliq retrievals over the Tibetan Plateau for both frozen and thawed soils based on both SMAP TBH and TBV measurements.