Combination of fully focused sentinel-6 and interferometric CryoSat-2 to enhance sea ice retrievals

Abstract

Radar altimetry has proven to be key in Earth observation when retrieving remote and systematic data for looking at long term trends, this is the case of the cryosphere monitoring. In this context, important missions addressed for altimetry are Sentinel-6 and CryoSat-2, launched by ESA. This study conveys methods for retrieval and estimation of surface ice parameters and features by combining data from both of them. In a first phase, Fully Focused SAR data processed in Athabasca Lake, along with interferometric data from CryoSat-2, are combined to classify the visible features and estimate the signal source location. Here, the advantages of Fully Focused processing over Delay-Doppler processing are highlighted. In a second stage, four methods for sea ice concentration estimation are employed using Sentinel-6 data from the year 2021 in a small region of the antarctic Weddell Sea, one based in histogram clustering identification and the others based on curve fitting and local maxima isolation, waveform per waveform. The results show a good convergence between the fitting filters and the local maxima detection. Finally, the validation data from AMSR2 shows agreement with the time series trend in 2021.