The SMOS payload Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) measures the brightness temperatures at 1.4 GHz in full polarisation with incidence angles ranging from 0° to 65°. All four Stokes parameters are obtained. It has a global coverage every three days, whereas for regions north of about 50°N and south of about 50°S complete daily coverage is achieved up to 85°N and 85°S, respectively. The footprint varies from about 35 km at nadir view to more than 50 km at incidence angles higher than 60°.
The sea ice thickness is derived from the near nadir brightness temperatures (L3B brightness temperature) using a single layer emissivity model [1, 2]. The L3B brightness temperature product contains the daily averaged brightness temperature intensities gridded onto a polar-stereographic projection with 12.5 km grid resolution. The emissivity is mainly a function of bulk ice temperature, salinity and thickness. The bulk ice temperature is estimated from surface air parameters of JRA-25 reanalysis data and a zero-dimensional thermodynamic model . The bulk ice salinity is estimated from a sea surface salinity weekly climatology. The sea ice thickness is corrected for the influence of the thickness distribution function to account for the invalid assumption of a uniform plane ice layer . The latter correction leads to an apparent deeper penetration depth than previously reported . We apply no correction for the influence of ice concentration. Thus, one can expect an underestimation of ice thickness when there is open water within the SMOS footprint. We account only for the thermodynamic influence of a parameterized snow layer on the bulk ice temperature but do not account for the direct radiative effect .
Starting on October 17 2013 SMOS Sea ice thickness maps are updated daily and can be viewed in the LAS when choosing the current year.
The ESA changed the L1C product version from 5.05 to 6.20 starting on May 5, 2015.
Attention: Since October 21 2016 the new version 3 replaces version 2. Version 3 comes with an enhanced sea ice thickness retrieval as well as an improved uncertainty estimation.
Last data set update: today