QUANTITATIVE ANALYSIS OF GLACIERS CHANGES FROM PASSAGE CANAL BASED ON GIS AND SATELLITE IMAGES, SOUTH ALASKA

The physical aspects of three glaciers from Passage Canal have been identified by field research, satellite images, and Geographic Information System. The main objective of this study is to determine the melting area and to calculate the withdrawal rate of Billings, Learnard, and Whittier glaciers. The satellite images from Landsat sensors (1985, 1994, 1999, 2006, 2011, and 2013) helped us to remote sensing observations. To assess the retreat of glaciers, new layers with glaciers' limits reasoning on sixth time-comparable satellite images were created and used for quantitative analysis. The results show that the area of glaciers from Passage Canal was reduced during 1985-2013: Billings Glacier decreased by 2.334 km super(2), Learnard Glacier decreased by 0.726 km super(2) and, Whittier Glacier decreased by 1.836 km super(2). Spatial Analyst Tools was used to determinate the Euclidean Distance of Billings Glacier, Learnard, and Whittier glaciers to Passage Canal. The first set of results obtained indicates that movement of glaciers is active and retired. An average ratio of melting area were determined for the period from 1985 to 2013: Billings Glacier was 0.08 km super(2)/year, Learnard Glacier was 0.02 km super(2)/year, and Whittier Glacier was 0.06 km super(2)/year. These results indicates that retreat of glaciers is slow, but constant.