Measurements of glacier variation in the Tibetan Plateau using landsat data

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 is at present the primary, in many cases the only way to measure the state of glaciers. In combination with Geographic Information System (GIS), it provides an efficient tool to analyze the current state and changes in glaciers. We used a technique of integrated remote sensing and GIS to map and measure changes in glaciers using a 21-year series of Landsat images (from 1973 to 1994) and topographic maps of a study site on the Tibetan Plateau. The details of glacier fluctuation, such as area of glaciers and 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 m a(-1) to 105 m a(-1). The results show that Landsat data provide an important source of information for studies of glacier variation. (C) Elsevier Science Inc., 1998.