Uso de Imgens Sentinel–2 para Análises de Retração de Geleiras: Comparativo Entre Ambientes nas Latitudes 44ºS e 62ºS (Use of Sentinel–2 images for the retraction analysis of glaciers: comparative between environments in latitudes 44oS and 62oS)

Este artigo analisou as alteracoes de area da Geleira de numero 6 do Monte Melimoyu, Chile, 44° 5’S – 72° 51’W e as geleiras Ecology, Sphinx, Baranowski e Tower, na Ilha Rei George, Peninsula Antartica, 62° 12’S - 58° 28’W. Para o mapeamento da variacao de area das geleiras entre 2000 e 2017 utilizou-se duas imagens do programa Sentinel–2, aplicando o metodo de delineamento manual com classificacao visual dos alvos. Os resultados foram comparados com dados do GLIMS e do Centro Polar e Climatico para a analise da evolucao de area no Monte Melimoyu e na Ilha Rei George, respectivamente. As geleiras de ambas as regioes apresentaram continua retracao frontal nos periodos analisados e sao comparaveis em dinâmica de retracao frontal. A perda de area na geleira do Monte Melimoyu foi de 4,94 km² da area total em 1970 (de 13,23 km²). A perda de area nas geleiras da Ilha Rei George foi de 3,83 km² da area total em 1956 (de 13,94 km²). Os resultados indicaram uma tendencia geral das geleiras a retracao. As imagens Sentinel–2, com 10 m de resolucao espacial, possuem potencial para continuidade do monitoramento das mudancas ambientais da Criosfera. A B S T R A C T This work analyzed changes area of glacier Number 6 of the Melimoyu Mont, Chile, 44° 5’S – 72° 51’W and the glaciers Ecology, Sphinx, Baranowski and Tower, in King George Island, Antarctic Peninsula, 62o 12’ – 58° 28’W. The area variations mapping of the glaciers for 2000 – 2017 period was performed using two images of the Sentinel–2 program and the glacier outline manual delineation method applying. The results were compared with GLIMS and Centro Polar e Climatico data for glaciers area evolution analyses. The glaciers of both regions showed continuous frontal retreat in the periods analyzed and are compared in frontal retreat dynamic. The loss of area in glacier of Melimoyu Mont was 4.94 km² of the total area in 1970 (13.23 km²). The loss of area in glaciers of King George Island was 3.83 km² of the total area in 1956, of 13.94 km². The results indicate a general retreat process tendency of the glaciers for period. The images of Sentinel–2 have potential for continuity environment changes monitoring in the Cryosphere. Keywords: Glaciology; Geomorphology; Retreat; Sentinel – 2; North Patagonia; Antarctic Peninsula.