Variation Regularity And Causes Of Typical Glaciers In The Tibetan Plateau In Recent 40 Years

Glacial changes are a major indicator of climate change and one of the most important factors in climate change.Since the 20 th century,the rapid rise in temperature has led to the shrinking of glaciers around the world,further affecting the water cycle and the ecological cycle.Tibetan plateau is the world's highest plateau,there are a lot of glacier,glacial retreat sharply affect the climate of the region and the surrounding area,water resources and the stability of the ecosystem,therefore,to study the regional glacier change is of great significance.This article mainly for nearly four decades of qinghai-tibet plateau region,pull two typical area upstream kernel fault glacier area and the west side of nyenchen tanglha glacier area in remote sensing data collection,data processing,to experiment with different glacier information extraction method,comparative analysis precision of each method,choose the most suitable method for glacier information extraction,and analyze the glacier dynamics in 40 years,at the same time,combining with the research state of regional climate data,terrain analysis the main factors influencing the glacial changes in the study area.The main findings of this paper are as follows:(1)Using different glacier information extraction method for the same area glaciers can be found that the band ratio method,principal component analysis(pca)and supervised classification and unsupervised classification,a glacier information accuracy of snow cover index method after processing,there is a big error on visual interpreting law compared with high precision,all kinds of methods mentioned above through many times experiment study area within a small area,improve the interpretation accuracy,then comprehensive analysis of information extraction of glaciers.(2)Ong pull kernel upstream glacier area glacier area overall wrong about 30.36 km2,area total withdrawal proportion was 12.82%,the annual average area of the shrinking rate is 0.759 km2* a-1,namely 0.32% * a-1.Nyenchen tanglha western glacier area overall retreated glacier area is about 63.69 km2,area total withdrawal proportion was 6.98%,the annual average area of the shrinking rate of 1.592 km2 *a-1,namely 0.17% *a-1.(3)The region's glaciers in 1976 and 2015 were 64.15 km3 and 53.31 km3.The total change in glacier reserves was 10.84 km3.The glaciers in the area of the tangeran area of the tangeran area were 396.62 km3 and 335.82 km3 in 1976 and 2015 respectively,and the total change in glacier reserves was 60.8 km3.(4)The results of glacier change and the analysis of meteorological data show that the main factors affecting the change of glacier include climate and topographic factors.Drastic changes of climate factors not only let two area be consistent in the glacier change rule,at the same time also make two different climate factor gap area glacial changes exist difference.The influence of other topographic factors has a large effect on the area of the glacier and its orientation.