Response Of Glacier Variation To Climate Change In The Himalayan Mountains,during The Last40Years

This paper selects five sample regions in the Himalayan as study area, and utilizes Landsat series satellites remote sensing images of1972,1980,1990,2000and2010as data source. Data of area change and other attribute of glacier systems used in this paper were obtained from the remote sensing records and the statistic records which have been published to discuss the diversities of glacial area change. At the same time, Based on the meteorological data include CRU TS3.1and data of stations, the spatial characteristics and process of climate change was analyzed. Furthermore, the relationship between climate change and glacial area change in the diverse region, the time lag between the force (the climate index) and the response (the change of glacial area) need to be calculated. The main results are as follows:Glacier Changes1. From1972to2010, the area of glaciers presented obviously shrinking trend in the five sample region. In the western Himalayan Mountains have shrink by0.51%·a-1from2408.73km2in1980yr to2105.25km2in2010yr. In the middle of Himalayan Mountains have shrink by0.62%·a-1. In the eastern Himalayan Mountains have shrink by0.45%·a-1, this rate is little than western part and middle part, Consider process of change, since1990, glacial retreat rate was significantly accelerated. The retreat rate reach0.63%·a-1,0.89%·a-1,0.52%·a-1in western, middle and eastern part of Himalayan.2. The limit of elevation can nurture glaciers in the eastern and middle part is lower than western Himalayan. There are sensitive elevations. One is elevation of glacier tongue, the other one is elevation of small-scale glaciers.3. The glaciers in each aspect of the sample region are retreating during1972to2010. The rate of retreat in the different aspect hasn’t obvious difference. So glacial recession is a complex problem in the small-scale, the rate of retreat was decided by the interaction between the terrain and climate. Climate change1. Temperature in the vicinity of the study area overall showed a warming trend in recent50years. The rate of increased annual mean temperature is0.37℃·(10a)-1had recorded by16weather-stations, this rate is faster than the rate in the Qinghai-Tibet Plateau(0.25-0.37℃·(10a)-1). The warming rate in the western and middle part is greater than the rate in the eastern part, and slop facing south is greater than slop facing north. Variation trend of temperature in different period was recorded,1960-1970\1975and1980-1985\1990was lower level, the increase trend began in1995.2. Although annual precipitation went up and down depending on year, the general characteristics show that the precipitation in the southern slope had reduced by-1.29mm·a-1, whereas the precipitation in the southern slope increased by0.65mm·a"1. This situation may be lead to a warm-dry trend in the southern slope and a warm-wet trend in the northern slope.3. The spatial-temporal characteristics of the three leading modes of the annual mean temperature and the precipitation are investigated for the period1950to2009. The results indicate that the first mode of temperature represents warm trend, since1995warm trend is more obvious, moreover the increasing extent of temperature in the north greater than that of south. The first mode of precipitation is a single-signed loading pattern and sensitive area is in the eastern Himalayan Mountains. The second mode shows the spatial variability of southern slope and northern slope. Dry trend happened in the southern slope.The relationship between glacier changes and climate changes1. Temperature was a significantly increase that is the fundamental reason of the continuing retreat of the glacier. The rate of increased temperatures in the western and middle of Himalayan greater than in the eastern part is the main reason for spatial variability of rate of glacial retreat. Since1995, temperature significantly increase is a turning point for glacial area change, glacial change got into a rapid change period.2. Evidences indicated that there is a phase lag of about0-3years for glacial area variation to annual mean temperature. But compare with annual mean temperature, annual minimum temperature has greater correlation with glacial area change.