Thickness of thin sea ice combined data product from SMOS and SMAP

The spaceborne passive microwave sensors Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) provide brightness temperature data at L-band (1.4 GHz). At this low frequency the thickness sea ice up to 50 cm can be derived. Thin sea ice occurs during the freezing season. In the melting season, the thickness of sea ice is highly variable and the emission properties in the microwave change due to the wetness of the surface and occurrence of melt ponds in the Arctic. Therefore, thickness data are calculated only during the freezing season, that is from October to April in the Arctic and from March to September in the Antarctic. During the melting season, the procedure does not yield meaningful results. SMOS data covers a large incidence angle range whereas SMAP observes at a fixed 40° incidence angle. The combined thickness of thin sea ice data product from both sensors is more stable and less RFI affected than the products from the single sensors. The daily updated data product is available from XXX.
As the resolution of both sensors is about 40 km, only larger regions of thin ice will be retrieved correctly. The rim of thin ice shown in many cases not necessarily indicates thin ice, but can also be caused by the smearing effect (convolution) of the low resolution.