A novel downscaling methodology for intermediate resolution radiometer data for SMAP

A novel downscaling methodology for intermediate spatial resolution radiometer data is developed in view of forthcoming SMAP mission. It is based on an active and a passive microwave forward model coupled by its ancillary parameters. The combined active/passive model introduced in this work yields backscatter and emission observations relation consistent with Aquarius/SAC-D observations and with what it has been reported in previous papers. Furthermore, merging spatial resolution between radar-derived and radiometer-based brightness temperature (Tb) is performed in a least-square framework. Methodology is tested using a synthetic numerical simulation example which showed that this approach leads to an increase of downscaled Tb accuracy.