Retreating Glaciers of the Himalayas: A Case Study of Gangotri Glacier Using 1990-2009 Satellite Images

Retreating Glaciers of the Himalayas:
A Case Study of Gangotri Glacier Using 1990-2009 Satellite Images
Jennifer Ding
Texas Academy of Mathematics and Science (TAMS)
Mentor: Dr. Pinliang Dong
Department of Geography, University of North Texas, Denton, TX 76203
Abstract
Glacier retreat has received increased attention as a sensitive indicator of global
warming. Based on medium-resolution Landsat Thematic Mapper (TM) images
acquired between 1990 and 2009, high-resolution GeoEye IKONOS images acquired
in 2005, and a digital elevation model (DEM) provided by NASA's Shuttle Radar
Topographic Mission (SRTM) carried out by the space shuttle Endeavour in 2000,
this study focuses on the spatial and temporal variation of the moraine-covered
Gangotri Glacier - one of the largest glaciers in the Himalayas. Image calibration
was carried out to convert Landsat TM digital numbers (DN) into radiance and
reflectance for better comparison between images acquired on different dates.
Reflectance spectral curves were derived from both glacial and non-glacial features
for more accurate image interpretation. IKONOS images were used for accurate
mapping of glacier terrain features. SRTM DEM was used to determine glacial flow
directions and aid in image interpretation. Multi-temporal analyses of Landsat TM
images acquired in 1990, 2001, and 2009 show that the Gangotri Glacier retreated
345 meters from 1990 to 2009, with a retreating rate of approximately 18 meters per
year. The results also show that there are no obvious changes in glacial retreating
rates during 1990-2001 and 2001-2009. However, the River Ganges may potentially
become a seasonal river as a result of continued glacier retreating, affecting hundreds
of millions of people on the Indian subcontinent.
1. Introduction
A glacier is made up of fallen snow that compresses into large, thickened ice masse over
many years. A moraine is any glacially formed accumulation of unconsolidated glacial debris
(soil and rock). Ice, snow, and glaciers have important effects on land surface temperature and
air/soil moisture. They are also important freshwater resources through surface runoff. Glacier

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Ding, Jennifer & Dong, Pinliang. Retreating Glaciers of the Himalayas: A Case Study of Gangotri Glacier Using 1990-2009 Satellite Images. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc84326/. Accessed September 21, 2014.