Global Volumetric Soil Moisture Derived from Satellite Infrared Measurements

We have initially developed a simple effective scheme to derive volumetric soil moisture (VSM) from infrared (IR) land emissivity retrieved from satellite measured IR spectral radiance. This novel scheme is applied to a 10-year period of global IR emissivity data retrieved from MetOp-A Infrared Atmospheric Sounding Interferometer (IASI) measurements. The VSM calculated from the IR emissivity (denoted as IR-VSM) is compared with that retrieved from satellite microwave (MW) multi-sensor measurements (denoted as MW-VSM). Monthly-mean spatial-gridded climatology datasets are generated to demonstrate VSM spatial variation as well as its seasonal-cycle and inter-annual variations. Samples of IR-VSM seasonal-cycle and inter-annual variations are shown and compared with those of MW-VSM. Initial positive agreement was found between IR- and MW-VSM, indicating that IR land emissivity contains water content information and converted soil moisture is consistent with that from MW measurement.