Year of Award

2009

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Geography (Cartography and GIS Option)

Department or School/College

Department of Geography

Committee Chair

Ulrich Kamp

Commitee Members

Anna Klene, Joel Harper, Tobias Bolch

Keywords

ASTER, GIS, Glaciers, Himalaya, India, Ladakh, Mountains

Abstract

Glaciers in the Himalaya are often heavily covered with supraglacial debris, making them difficult to study with remotely-sensed imagery alone. Various methods such as band ratios can be used effectively to map clean-ice glaciers; however, a thicker layer of debris often makes it impossible to distinguish between supraglacial debris and the surrounding terrain. Previously, a morphometric approach employing an ASTER-derived digital elevation model (DEM) has been used to map glaciers in the Khumbu Himal and the Tien Shan. This project aims first to test the ability of the morphometric procedure to map small glaciers; second, to use the morphometric approach to map glaciers in Ladakh; and third, to use Landsat and ASTER data and GPS and field measurements to monitor glacier change in Ladakh over the past four decades. Field work was carried out in the summers of 2007 and 2008. For clean ice, a ratio of shortwave infrared (SWIR, 1.6-1.7 µm) and near infrared (NIR, 0.76-0.86 µm) bands from the ASTER dataset was used to distinguish snow and ice. For debris-covered glaciers, morphometric features such as slope, derived from a DEM, were combined with thermal imagery and supervised classifiers to map glacial margins. The method is promising for large glaciers, although problems occurred in the distal and lateral parts and in the forefield of the glaciers. The morphometric approach was inadequate for mapping small glaciers, due to a paucity of unique topographic features on the glaciers which can be used to distinguish them from the surrounding terrain. A multi-temporal analysis of three glaciers in Ladakh found that two of them have receded—one since at least the mid-1970s, the other since at least 2000—while a third glacier, Parkachik Glacier, seemed to have retreated in the 1980s, only to advance in the 1990s and early 2000s. However, from 2004-2008 it showed only negligible change making its current status difficult to determine without further monitoring. The glacier outlines derived during this project will be added to the Global Land Ice Measurements from Space (GLIMS) database. In testing the limits of the morphometric approach, the thesis has provided a valuable contribution to the present literature and knowledge-base regarding the mapping of debris-covered glaciers.

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© Copyright 2009 Martin Edward Byrne