Sensitivities to ocean and sea ice parameters as a function of CIMR channels for arctic, mid-latitude, and tropical conditions.

The figure illustrates the sensitivities of the low passive microwave brightness temperature at the top-of-the-atmosphere, in terms of Sea Surface Temperature (SST), Sea Surface Salinity (SSS), Ocean Wind Speed (OWS) and Sea Ice Concentration (SIC) as a function of frequency from 1 to 40 GHz. The Copernicus Imaging Microwave Radiometer (CIMR) channels are indicated at the top of the figure. Three different geophysical conditions are considered: arctic, mid-latitude and tropical. For each parameter the sensitivity is normalized by the maximum of sensitivity between the three considered environments, for the full frequency range from 1 to 40 GHz.

The sensitivities have been computed using the ocean radiative transfer model of Remote Sensing Systems (Meissner and Wentz, 2012), the sea ice emissivities estimated from the ESA sea ice Round Robin Data Package (Pedersen et al., 2019), and the atmospheric radiative transfer model of Rosenkranz (Rosenkranz, 2017).