| Nepal Himalaya, located in the south of the Qinghai-Tibet plateau, becomes one of the world’s largest glacierized areas by virtue of its high terrain. The glacier not only is a kind of precious freshwater resource, but also a natural indicator of climate change. The glacier retreat and sea-level rise have become an indisputable fact which is closely related to global warming. Therefore, study on structure characteristics of glacier system and its changes in this area, is of great significance in terms of both science and society. The study area in this article is Nepal, which is located in the south of middle Himalayas. Based on glacier catalogue date of Nepal, DEM, etc., using GIS technology and Excel, Spass software, and relying on theory of glacier system, the structure characteristics of glacier system and glacier changes is analyzed. The main results are as follows:1) The structure characteristics of glacier system. In terms of quantity, the total numbers of glacier is 3808, the total areas of glacier is 3902.44 km2, and total reserves is up to 312.42 km3, the average area of single glacier is 1.02 km2, and average reserves of single glacier is 0.08 km3; In terms of distribution, the range of longitude distribution of glacier in Nepal is from 80.81°E to 88.18°E, and the range of latitude distribution of the glacier in Nepal is from 27.53°N to 30.38°N; In terms of altitude, the distribution characteristics with different altitude for glacier area in glacier system are similar to normal distribution, the glacier area, accounting for 85% of the total area of the glacier in Nepal, are mainly distributed in range of 4850～6250m above sea level; In terms of size, the distribution rules with the change of area for glacier size are general compliance with normal distribution. The glacier size is small in the whole Nepal, it is mainly less than 1 km2. The number and area are account for 90.7% and 36% respectively in overall glacier. There are only 355 (account for 9.22%) glaciers that a single glacier area is more than 1 km2, but its total areas are account for 63.90%;In terms of direction, the south direction has obvious advantages in all directions. The number (number, size, reserves) is the most and the size is the maximum. The number, size and reserves are account for 39.14%、53.05% and 62.27% respectively; In terms of coverage, the coverage of different levels of glacier system are from 0.01 to 0.15, belonging to the dispersed glaciation zone.2) Equilibrium line field of glacier system. The Equilibrium line field in Nepal was established on the basis of GIS technology and Kriging interpolation method. The Distribution characteristics are as follows: ① Lower in the south and higher in the north, and increased gradually from south to north.② the Equilibrium line field are intensive in the east area and sparse in the west area.③ the spatial distribution of equilibrium line are complex and it’s appeared a number of high value area with the peak centered.3) Glacier changes. The glacier variations are characterized by a general trend of "decrease in area、mean area and volume of glacier and increase in number " in the Nepal Himalayas during the past 30 years. The glacier number increased by 378, the area and volume of gl acier are decreased by 1266.134 km2 and 128.84 km3 with a rate of +0.31%/a,-0.83%/a and -1.02%/a. Glacier variation also pre sent the trend:decrease in area and volume on the horizontal dir ection. The annual variation of glacier area between 3150-8650m is large differences in the whole Nepal, which is ranging 0.01%/a to 3.33%/a. In terms of glacier variation of different levels of sc--ale:each grade glacier area showed retreat trend, and the smalle r the size, the greater the retreat. At the same time, the glacier scale is smaller and smaller with the smaller median size. In ter ms of glacier changes on different faces:glacier areas are retreati ng in different orientations except the north and northwest. The g lacier in southeast are shrinked fastest with a rate of 1.40%/a, w hile the glacier in northeast retreated slowest with a rate of 0.20%... |
PDF Full Text Request