Evaluation of automated and manual methods for measuring change in kolahoi glacier using geospatial technology

Glaciers are the important components of earth’s natural system and are sensitive indicators of climate change. Their accurate mapping and monitoring is inevitable for planning and management of water resources. Remote sensing and GIS has played an important role in mapping and monitoring of glaciers, considering their extent and inaccessibility. A number of methods using multispectral data are available, such as visual interpretation, band ratioing and spectral indices. An automated method (including spectral indices NIR/SWIR, NDWI, NDDI, TGM and Slope) was used for mapping various glacier terrain classes. Temperature and spectral difference between debris and non-debris covered parts of glacier enabled their differentiation by using different threshold values. The glacial extent derived from automated method was more accurate than that obtained from visual interpretation as it was capable of delineating debris-covered ice by incorporating thermal information. Thus automated method was accepted for delineating the change in Kolahoi glacier from 2001 to 2010. Trend analysis showed that the mean annual temperature (TMax and TMin) has increased and there is insignificant decrease in the total annual precipitation in the area. The rising temperature and declining precipitation might have contributed to the glacier recession in the area. However, anthropogenic activities like movement of Bakerwall tribe, pollution caused by the emission of greenhouse gases, military vehicular movement, cement plants and annual religious pilgrimage in the vicinity of glacier may also be expediting the recession of the glacier. Therefore, sound efforts need to be taken in order to save this precious source of water.