Mapping the concentration of sea ice in the central antarctic peninsula with sentinel 1 data

Abstract

Sea ice acts as a thermal insulator between the ocean and the atmosphere and without it, the ocean will be free to emit heat to the atmosphere, influencing the formation of water bodies and ocean circulation. This article proposes the classification and identification of sea ice by means of Synthetic Aperture Radar (SAR) images in the C band, obtained by the Sentinel 1B satellite, Extra Wide Swath (EW) imaging mode under HH + HV polarizations, radiometrically calibrated and normalized to incidence angle at 30°. The study area covered the central oceanic region of the Antarctic Peninsula during the winter and early austral spring of 2018. Obtaining samples for the classification of SAR scenes was obtained through visual analysis of the target texture in Sentinel 2 optical images (Multispectral Instrument), false-color RGB compositions of the HH and HV polarizations (R-HH, G-HV, B-HV/HH and R-HH, G-HH, B-HV) and unsupervised classification through cluster analysis. Backscatter coefficients (σ°) were identified in the HH polarization of-8.0 to-12.6 dB for young ice and/or first-year ice,-2.1 to-7.3 dB for multiyear ice, and for the HV polarization of-19.3 to-24.2 dB for young ice and/or first-year ice and-6.8 to-13.4 dB for multiyear ice, making it possible to map the concentration of sea ice in the region of study by using these thresholds.