Remote Sensing Monitoring Of Glacier And Snow Cover Changes In The Kunlun Mountain

This study is presented of the geographical distribution and spatial and temporal variability of the Kunlun Mountain glacier （1976-2010） and snow cover （2002-2010）. The main data comes from Landsat TM\ETM+images, daily MODIS snow cover product and the temperature and precipitation data from selected meteorological stations across western China. Digital elevation model was used to better understand the spatial pattern on the different altitude of the snow cover and glacier area.A multiple linear regression analysis and spline method was conducted to interpolate temperature and precipitation of Eastern Kunlun Mountain. The correlation analysis method was performed to show the association of inter-annual variations between snow cover and snow season temperature as well as precipitation. The main conclusions are listed as follows:（I） Characteristics of glacier and snow cover change1) There were glaciers of Kunlun Mountain in1976with the area of9962km², the glacial area reduced to8718km²by2010with the retreating rate of12.5%. This time series shows reductions over the past30years with most of the reductions occurring in the1990-2000of0.67%yr^-1. However, there is surge glacier of the Western Kunlun Mountain and some glacier area keep stable in the past decades. The glacier lake expands gradually and there are seven new glacier lakes forming.2) The retreat rate decreases as the elevation increases. It arrived to zero around5500m and means that the glacier keeps stable. We defined this elevation as the upper limit of retreated zone and it has the range of5000-6600m, and it increases gradually in1976-2010in the central and eastern part of mountain.3) Kunlun Mountain experienced an increase in snow cover and snow cover duration in2002-2010. The snow cover and snow cover duration of seasons increased expect for the spring. We find a highly heterogeneous spatial pattern of changes in snow cover duration. It increased gradually and kept stable within6500m of altitude, then fell slowly. Interestingly, it went up to360days dramatically around7500m. The rate of snow cover duration increased and then fell, and finally it kept stable.（Ⅱ） Glacier area and snow cover response to climate change1) The linear warming rate was0.35℃10-1yr-1and precipitation increased at the rate of6.2mm10-1yr-1. The inner Kunlun Mountain had the biggest temperature growth rate but lowest precipitation growth rate. The temperature grew obviously in spring and the precipitation increased evidently in summer. The precipitation growth rate was higher in relatively higher elevation while the growth rate of temperature was not obvious.2) The retreat of glaciers in the Kunlun Mountains was mainly resulted from the temperature rising. Though the precipitation increased slightly in1961-2010and it contributed to the increased glacier area in accumulation area.3) The snow cover duration was in agreement with increasing precipitation and show negative correlation with temperature. The rate of precipitation and temperature change were relatively slower and higher in the central of study area respectively, which was well correspond to the low growth rate of snow cover duration.4) The elevation zone （5500m） that snow cover and snow cover duration experienced the maximum was well conrespond to the the upper limit of glacier retreated zone, and it is also the upper limit of snow increased zone. The distribution of spatial pattern of snow cover acts as an indicator of precipitation, especially in high elevation zone. Therefore, we concluded that the altitude of around5500m experienced the maximum precipitation of Kunlun Mountain.