Main Structure Characteristics And Variation Of Glacier Systems Responding To Future Climate Changing In Tarim River Basin

Tarim River Basin glacier system, is one of the largest glacierized area in China, where glacier area amounts to 20249. 3km2 and accounts for more than one-third of the total glacier area in China. Along with the enlargement of the scale of the exploitation and climate changing , Tarim River Basin's glacial run off contribute increasingly to its flourishing and development , since near 50% of Tarim River run off is composed of glacial run off averagely . So Tarim River Basin s glacier systems characteristics and variations have been concerned closely. The main results and detailed contents were revealed as following:(1) Based on the difference of mountains and streams between, three sub-glacierized area was schemed: the south , Karakorum-kunlun mountains glacierized area; the north , southwest Tianshan mountains glacierized area; the west, Pamirs glacierized area .(2) According to the linear relationship between ELAh and Hme, ELAhc (calculated snow line) can be obtained. Based on the calculated results, the distribution of ELAhc was mapped. Further study about minimum glacier size to climate oriented in glacier system (Slim) and climate snow line (Hcli) has been carried out. The results say: small glaciers ELAhc vary widely in glacier system, but with the enlarging of glacier size, the ELAh, will be fixed at a certain narrow range, where climate snow line was involved; Both the distribution of ELAhc and Heli show that varying from south to north, the Heli goes down from about 5700(m) to 4000(m) as a whole because of the difference of latitude, and from west to east, the Hcli also differs with the increasing of longitude because of water vapor changing from west to east.(3) Understanding about the structure characteristics of glacier system well will favor to predict the variation of glacier system responding to the climate changing in Tarim River Basin. The structure characteristic of amount (number, area, volume) in two aspects: based on mountains, more than 60% were living inKarakorum-dunlun mountains; based on watersheds, there were 50% or more in Yarkant River and Hotan River drainage basins. The structure of altitude parameters indicate that the altitude where the glacier area under it equaled the glacier area above it (Fmed) was little high than, the maximum area altitude (Fmaxel) and average altitude (Hue) because larger glaciers, who extended to much higher mountains, made the top part of glacier area relatively enlarge. HSR, i. e. the ratio of glacier area near the maximum area altitude (Hmaxel) against the whole glacier system' s area, were larger where smaller glaciers were comparatively intensive than where bigger glacier prevailed. Both the amount and concentration index of various glacier sizes analyzing showed that glaciers in small size were rich in number, and glacier in large size gathered most of the volume, while the glaciers in different sizes relatively equal in area in glacier system. As a whole the calculated MR of glacier system were reliable, which showed the glacier systems in south of Tarim River Basin were more than 0.7 which reflected the characteristic of extremely-continental glacial region, whereas the glacier systems' AAR in north of Tarim River Basin were less than 0. 7, which pronounced the characteristics of sub-continental glacial region. (4) On the basis of the structure of the glacier system and the nature of the equilibrium line altitudes at steady state, functional model of the variation of glacier system are established, using Kotlyakov-krenke' s equation relating annual ablation of glacier and mean summer temperature. The effect of decreasing air temperature due to rising of ELA, reduction of glacier area, and the increasing of accumulation due to the increasing of precipitation were considered in these models simultaneously. The modeling results under the climatic scenarios with temperature and precipitation increasing indicate that the glacial run off fed by sub-continental type glacier systems with relatively high levels of mass balance are sensitive to c...