The Glacier Variation Of Tibetan Plateau Under Different Climate Changes Scenarios

The study is about the glacier variation under different climate change scenarios of Tibetan Plateau. Based the introduction of the nature geogrphice characteristic of Tibetan Plateau, the analysis on the characteristics of the Tibetan Plateau glacier system and the feature analysis of the recent climate variation of Tibetan Plateau, the glacier variation features under different climate change scenarios are discussed on the glacier system model. There are two basic climate change scenarios of the climate change, which include temperature rising and temperature decreasing. Its obtained some standpoints followed.First, there are 36924 glaciers scatters around Tibetan Plateau, which total area is 50657 square kilometers and its total volumn is 4680.5 club kilometers. The ratio of the Tibetan Plateau glacier to China glacier is 79.6%,85.2% and 83.6%, in sequence. The big glacier influences the scale of glacier system more obvious than the small one. There are two great features about the equilibrium-line altitude distribution of Tibetan Plateau. One is the equilibrium-line altitude lifts gradually form the Southeast to the Northwest, and there is close center in the Northwest Tibetan Plateau. Another one is the gradient of the equilibrium-line altitude change is high at the rim of the Tibetan Plateau, while it is smaller at the center of the Plateau. As a whole, the features of the glacier distribution of Tibetan Plateau are influenced by the unique nature geographic condition of the huge mid-latitude plateau of Tibetan Plateau obviously.Second, the temperature of Tibetan plateau is rising and the velocity is about 0.35?/10a generally. The winter average temperature is rising quite rapid than the summer average temperature. At the same time, the temperature of the high altitude regions increased more quick than the low altitude regions. The velocity of the temperature rising seems enhanced in the last decadal. The annual precipitation increased in the rate about 9.2mm/10a of Tibetan Plateau. In Tibetan Plateau, except of the summer, the average precipitation increases gradually in the other three seasons, while the highest increasing rate is 17.6mm/10a, in winter. The precipitation variation cycle of Tibetan Plateau is changed about 1980y, the two cycles (6a and 22a) insteaded by the lla cycle around the time hinge. The relative humidity of the Tibetan Plateau increased weakly, also.Third, under climate warming scenarios, the glaciers of the Tibetan Plateau shrink continually and die out eventually in generally. The velocity of the temperature rising effects the glacier variation speed significantly. Take as it is stable climate change states in the future, the glacier area of Tibetan Plateau will shrink to about the one of three of thel980's in the end of the 21st century. And the volumn of the glacier of the Tibetan Plateau will be about one of four of the level of 1980's state. The sensitivity of every glacier system is relatively conservative in the response to the climate change, that is, the sensitive glacier system will be more sensitive than the stable glacier system under the same climate change background always. Furthermore, the small glacier is more sensitive to the temperature rising than the big glacier. The continually temperature rising brings with the increase of the glacier melt water at the beginning period of the glacier shrinkage of the Tibetan Plateau. And it companies with the higher variability of the amount of annual glacial melt water. The feature of the glacier melt water variation takes disadvantage to the usage of the water resource of the Tibetan Plateau and its surrounding regions.Fouth, the glacier area will enlarge under the temperature decreasing scenario. The velocity of the temperature decreasing influences the variation of the Tibetan Plateau obviously, which impacts the process of the glacier area variation and the procedure of the glacier melt water volumn at the same time. The variation of the glacier melt water is complex under the temperature decreasing scenario more than the feature under the temperature rising scenario. The curve of the glacier melt water variation under the temperature decreasing scenario is quite different as the deceasing velocity change.The last, but not the least, the main feature of the tendency of the glacier melt water runoff is it increases in the start period and decreases in the last period in higher speed under the different climate change scenarios. On the other hand, the characteristics under different climate change scenarios are different to each other. In details, the glacier area will last shrink until die out if the temperature rising consistently, while the glacier area will enlarge as the temperature decreasing. In spite of the difference of the tendency of the glacier variation under different climate change scenarios, the sensitivity of the glacier system will stable always.