Estimation of the AMSR2 Data Potential to Retrieve the Arctic Sea Ice Thickness

satellite measurements of the Advanced Scanning Microwave Radiometer 2 (AMSR2) have been analyzed to estimate their potential to retrieve the Arctic sea ice thickness. The AMSR2 measurement data have been processed with the recently developed method to account for the atmospheric microwave radiation parameters to calculate the gradient differences (GDs) between the vertically polarized sea ice emission coefficients at the AMSR2 frequencies of 6.9, 10.65, 18.7, 23.8 and 36.5 GHz. It has been shown that the values of GDs are essentially different for the major Arctic sea ice types (Multi-Year, First Year and Young ice), but the ranges of their variability for every type are comparatively large. It has been suggested that the variability of GDs inside one and the same sea ice type is largely ensured by the sea ice thickness due to strong influence of the sea ice salinity on its dielectric properties. The three GDs have been matched up with the sea ice thickness (d) taken from CryoSat-2 altimeter product. For correct matching up the AMSR2 Level 3 data have been processed to obtain 30-day brightness temperature averages which have further been used to calculate GDs on the CryoSat-2 data grid. The collocation of the AMSR2 retrieved GDs with the CryoSat-2 d data has been done for January–April and November and December months of 2020. It has been shown that the correlation between d and GD constitutes ∼ 0.8 for every of the three GDs. A Neural Network algorithm has been trained to estimate the sea ice thickness using all the three GDs as input parameters. The sea ice thickness maps have been built with the NN algorithm showing physically reasonable results corresponding to known Arctic sea ice type distribution in different Arctic areas.