The Study Of Glacier Changes In Typical Regions,China Tianshan Mountains

In China Tianshan mountains,where developed a large number of glaciers,the water storage is an important guarantee of society and economy of Xinjiang province.Under the background of global warming,these glaciers undergoning the corresponding changes.To systematically know the glacier changes and causes in the mountains,this paper selected five sample regions in China Tianshan(a region located in Dzungarian Alatau mountain,b region located in westernmost Haerketawu mountain,c region located in Nalati mountain,d region located in the Tianger mountain and southeast of Elianhaerbiga mountain,e region located in Harlik mountain).Based on the Landsat TM/ETM+ remote sensing images,we used the combination of computer automatic interpretation and visual interpretation method to obtain glacier boundary information of 1990s,2000s,2011s in the five sample regions,and then used GIS technology to study the distribution and change of glaciers in different scales,different altitudes and different aspects.Afterwards,we used the ground climate data and upper air data to study the spatial-temporal characteristics of annual average temperature,annual precipitation,summer temperature and warm season precipitation in the period of 1960-2011 in Tianshan.Based on these,we analyzed the response relationship between glacier and climate change in these five sample regions,and preliminary conclusions are as follows:(I)Characteristics of glacier distribution and change1)In the 1990s,the glacier area of five regions were:a region is 334.22km2,b region is 2248.16 km2,c is region 55.11 km2,d region is 550.55 km2,e region is 122.45 km2.In 1990-2000,c and d region had the highest glacial shrink rate,a and b region come second,and the e region was the slowest.In 2000-2011,glacial recession accelerated in all the five sample regions.And the shrink rate of a region exceeded b region,and c region also exceeded d region.2)From the view of scale,the glaciers in five sample regions were all mainly 1-5 km2 in 1990s.In large-scale glaciers,the single glacier of b region is generally larger than a region.There are more glaciers which are less than 1km2 in c and d region.The glaciers in e region are mainly focused on the scale of 1-20km2.In recent 21 years,the glacier scale of 0.01-0.1 km2 increased,and other scale of glaciers reduced in a,b,c and d region.But in e region,the glacial recession are mainly from 5-20km2 to 0.1-5km2.3)From the view of altitude,glaciers in b,d and e region focused on an altitude of 4000m,and glaciers in a and c region are below this height.The trend of glacial shrink in the five sample regions is basically consistent.Below the altitude of 4000m,the glacial recession rate varied with altitude presented a more obvious change.On the same altitude,glacial recession rate in a region was obviously lower than other sample regions.4)From the view of aspect,in b region,the glaciers distributed evenly in each aspect,but in other four sample regions,glaciers mainly distributed in the north,northeast and northwest.In 1990-2011,glaciers shrinked-in every aspect,and in addition to b region,glacial recession mainly occurred in the south direction.(II)Climate change and the corresponding glacier response1)In 1960-2011,the annual average temperature,annual precipitation,summer temperature and warm season precipitation all presented the increasing trend in the five sample regions.In the five sample regions,the summer temperature presented obviously increasing trend,and warm season precipitation all increased,but not obviously.The height of 0? changes of summer showed that temperature of upper atmospheric in summer declined in southern china Tianshan,while in the north,it rose.2)a and b region are in the same longitude zone,a region has a large amount of precipitation,decreased in precipitation led to a larger shrinkage rate than b,c and d region are compared to the same latitude area,dramatic retreate of glaciers in c region due to the low altitude distribution of glaciers.e region's large-scale glaciers may be the mian cause of slow glacier shrinkage in this region.