Deriving glaciers variation integrated remote sensing and GIS in the Tibetan plateau

Glaciers on the Tibetan plateau play an important role in the Earth´s climate system. Because of high altitude and difficulties in access, regular, systematic surveys of glacier variation are almost impossible in some regions of the Tibetan plateau. As a result, remote sensing techniques are at present the primary, in many cases the only way to measure the state of glaciers. In combination with GIS, it provides an efficient tool to analyze the current state and changes in glaciers. The authors used a technique of integrated remote sensing and GIS to map and measure on the changes in glaciers using a 21-year series of Landsat images (from 1973 to 1994) and topographic maps on a study site on the Tibetan plateau. The details of glacier fluctuation, such as area of glaciers and the changes in the magnitude of recession or advance of a glacier terminus on different dates, are described based on the results of image analysis, including coregistration, classification, vector analysis, and area calculation. Within the study area, during the 21 years, it was determined that the northern glaciers advanced and the southern glaciers retreated, the average rate of change was 50 to 105 m a^-1. The results show that Landsat data provide an important source of information for studies of glacier variation