Mapeamento da concentração do gelo marinho na região central da Península Antártica com dados Sentinel 1

• Main Authors: Hillebrand , Fernando Luis, Bremer, Ulisses Franz, Arigony Neto, Jorge, Rosa, Cristiano Niederauer da, Mendes Junior, Claudio Wilson, Costi, Juliana, Freitas, Marcos Wellausen Dias de
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Backscatter coefficient; Synthetic Aperture Radar; Sea ice classification; Retroespalhamento; Imagens oticas; Antarctic; Antarctic Peninsula; Austral; Sob’; The Antarctic; The Sentinel; Antarc*; Antártica; Sea ice
• Online Access: http://hdl.handle.net/10183/216354

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. O gelo marinho atua como isolante térmico entre o oceano e a atmosfera. Sem este, o oceano estará livre para emitir calor à atmosfera, influenciando a formação de massas d’água e circulação oceânica. Este artigo propõe a classificação e identificação do gelo marinho por meio de imagens Synthetic Aperture Radar (SAR) na banda C, obtidas pelo satélite Sentinel 1B, modo de imageamento Extra Wide Swath (EW), sob polarizações HH + HV, radiometricamente calibradas e normalizadas ao ângulo de incidência a 30°. A área de estudo abrangeu a região oceânica central da Península Antártica durante o inverno e início da primavera austral de 2018. A obtenção das amostras para a ...