Analysis About The Change In Glacier And Lake And Its Response To Climate In The West Of The Tibetan Plateau

Cryosphere is one of the five research fields of the earth science. The glacier is theproduct of climate and also the highly sensitive indicator. Not only As thehighest-altitude region of the world, Tibetan Plateau is also the region in themid-latitude regions of the world where the glaciers and lakes developed. The globalchange(generally warming) is the hot issue of today’s Earth science research, and theregional climate response to global change is the focus of climate research in thecontext of global warming. The global change has great relation to the surface processchanges of Tibetan Plateau, in particular, glaciers and lakes. Rising temperatures willlead to melting of glaciers. As an important part of the water resources in arid andsemiarid zones, glaciers not only play a vital role in the balance of the regionalecological environment, but also is the solid reservoir of freshwater resources. Lake is anatural complex, and connected the comprehensive effects of the atmosphere, biosphere,soil and terrestrial water. The lakes on the Tibetan Plateau are inner lakes mostly, freefrom the anthropogenic activities, thus the evolution of the lakes can reflect the naturalclimate change honestly, is the indicator of climate and environment. Therefore, thestudy of the dynamic changes of the glaciers and lakes of the Tibetan Plateau hasimportant theoretical and practical significance of the global change research.Taking the southwest of the Tibetan Plateau region as a case, using the RS and GIStechnology, on the basis of the topographic map(1:250000), Landsat TM, LandsatETM+and the digital elevation model(DEM), after the process of projection andgeometric correction, image mosaic and bands stack, extracting the information ofglaciers and lakes. Thus, to study the changes and regional comparisons of the glaciersand lakes, explore its relationship with the altitude. Finally, this paper analysis the characteristics of the climate change of the study area, and the changes ofglaciers and lakes, as response to the climate change. The main contents and results ofresearch are as following:1. On the basis of the topographic map in1960, and the digital remote sensingimage in1990and2000, after the process of projection and geometric correction, imagemosaic and bands stack, extracting the vector information of glaciers and lakes.Then, counting the area of the glaciers and lakes in these three periods, thus to study thedynamic change and its different characteristics of the temporal and spatial variation ofglaciers and lakes.2. The study reveals that the glacier resources, mainly depends on the area,especially the volume of the glacier, not only the quantity. The large glaciers occupy animportant position in the total water resources and ice water circulation. The glaciers areretreating from1960to2000, and the total decreased area is1625.33km~2, the averagerate is40.63km~2a-1. The glaciers which≤0.50km~2and＞100km~2are mostlychanged. The tread of the glaciers is the increase of the small glaciers and melting of thehuge glaciers. At the meantime, the average rate of retreating is increased from40.13km~2a-1to42.13km~2a-1.3. he study area is divided into three pieces, namely5Q1,5Q2and5Q3. Throughcomparing the statistics of the glacier changes of these three regions, it reveals that theregion of5Q3takes the most important role in the glacier changes. From1960to2000,the share of quantity and area of this region are all greater than50%. The glaciers in thisregion are mainly located in the west of the Himalayas.4. The altitude of the study area is divided into7grades, they are≤3000m、3000～4000m、4000～5000m、5000～5200m、5200～5400m、5400～5600m、5600～5800m、5800～6000m and≥6000m. The altitude which distributed glaciers is5400～5800m. The area which its height＜4000m only accounts for a small part ofthe glaciers, and the region which its elevation≥6000m also has barely glaciersbecause of the narrow ridge. Over the situation of the glacier changes, the regionswhich their altitude between5400m to5600m,4000m to5000m and5600m to5800mtakes the greatest important role in the glacier changes. The areas of these regionsdecreased by659.34km~2,554.42km~2and487.27km~2, the change rations are77%,76%and55%respectively. And the glaciers has decreased in the region of which itselevation between5400m to5800m and4000m to5000m. At the same time, the areasof these regions which their altitude between5200m to5400m and5800m to6000m increased by137.40km~2and91.80km~2.5. The change of lakes area was obvious during last40years showed a trend ofreduction early and increase later. The rate of lake is changing smaller and smallerconstantly. The area of lakes in1960is176.48km~2, and it decreased to163.64km~2in2000, the average retreated rate is0.32km~2a-1.6. The fluctuated increase of the average annual temperature, the fluctuateddecrease of the annual precipitation and the annual evaporation are the characteristics ofthe climate change of the study area. The main factors caused glaciers’ retreating are thechanges of temperature and precipitation. The changes of precipitation, evaporation andglaciers’ melt dominated the lakes’ area.