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EnglishTropical glaciers in the northern Andes have retreated since the Little Ice Age (XVI-XIX), and this retreat has been accelerated since the second half of the twentieth century. In this study, variations in the area of glaciers in Colombia and Venezuela have been mapped using Landsat images, acquired between 1985 and 2015. Currently, in Colombia, there are glaciers in Sierra Nevada de Santa Marta, Sierra Nevada del Cocuy and volcanoes of Nevado del Ruiz, Santa Isabel, del Tolima and del Huila, while in Venezuela, it remains only a mass of ice in the Sierra Nevada Merida. The extent of each glacier was calculated by the Normalized Difference Snow Index (NDSI) method. After the application of a suitable threshold, the polygons with the area of each ice glacier were obtained. In 1985/1986, the sum of the areas of the seven studied glaciers corresponded to 92.84 km², while in the final year analyzed (2015/2016), this value shrank to 36.97 km². The area shrinkage occurred in all the glaciers that were mapped, with annual decline rates ranging from 2.49%/year to 8.46%/year portuguesAs geleiras tropicais do norte andino tem apresentado retracao desde o fim da Pequena Idade do Gelo (sec. XVI-XIX), retracao esta que se acentuou a partir da segunda metade do seculo XX. Neste estudo, a variacao de area das geleiras na Colombia e Venezuela foi mapeada a partir de imagens Landsat adquiridas entre 1985 e 2015. Atualmente, na Colombia, ha geleiras na Sierra Nevada de Santa Marta, na Sierra Nevada del Cocuy e nos vulcoes do Nevado del Ruiz, Santa Isabel, del Tolima e del Huila, enquanto na Venezuela, resta apenas uma massa de gelo na Sierra Nevada de Merida. A extensao de cada geleira foi mapeada atraves do metodo Normalized Difference Snow Index (NDSI). Apos a aplicacao de um limiar, foram obtidos os poligonos com as areas de gelo de cada geleira. Em 1985/1986, a soma das areas das sete geleiras estudadas correspondia a 92,84 km², enquanto no ultimo ano estudado (2015/2016) esse valor passou para 36,97 km². A reducao de area ocorreu em todas as geleiras analisadas, com taxas de retracao anual variando entre 2,49% a.a. e 8,46% a.a

VARIAÇÕES DE ÁREA DAS GELEIRAS DA COLÔMBIA E DA VENEZUELA ENTRE 1985 E 2015, COM DADOS DE SENSORIAMENTO REMOTO