| As the highest-atlitude region of the world, Tibetan Plateau is a unique geographical unit, where the cradle of many large rivers in China and East Asia. The Plateau has the important ecological function of ecological store water capacity, water conservation and climate regulation, so Tibetan Plateau has always been the scientists’ research hot spot by its special geographical position and role. Northern Tibetan Plateau is the most main distribution of the plateau lake and the biggest inland lake distribution area. Plateau lake change contains important plateau climate information, its formation and vanish, expansion, contraction and correlative evolution of ecological environment all caused by the worlds, regional and Local tectonic and climatic events together. So the study about changes of glaciers and lakes in a typical basin and their response to climate change is indispensable in global change research.This paper takes the northern plateau area as the study area, under the support of the state environmental protection commonweal industry research special (200809010),(200909050)(201209032). Based on the four stages of remote sensing images in1976,1990,2000and2010, the dynamics of the lakes with area over one square kilometers in Northern Tibetan Plateau was studied. Combined with the data of eight meteorological stations in recent45years, the relations between the dynamics of the lakes and the climate changes were also analyzed. The main results are as follows:(1) The number of lakes with area over one square kilometers in Northern Tibetan Plateau in the1976-2010four periods were675,707,777and789, presents a consistent increase trend. In the35years, the number of lakes has increased114, and the most significant increase amplitude was from1990to2000. In the Four periods, the total area of lake was23034.04km2,23167.24km2,24235.33km2and27441.95km2respectively, the area of lake increased4407.91km2from1976to2010, presents the slow first and then sharp growth tendency, with2000-2010in the area of the fastest growth, its growth rate was significantly higher than the1976-1990and1990-2000in the period.(2) Through the Nam Co, Selin Co and Duogerenqiang Co, three typical lake area of dynamic study, it is further verified the conclusion that the plateau lake increased in the35years. The area of Selin Co lake increased from1648.6km2to2332.6km2from1976to2010, an increase rate of41.5%, has exceeded the Nam Co lake and become the largest saline lake in Tibet.(3) In the past45years, the annual average air temperature, annual average highest air temperature, annual average lowest air temperature, precipitation and annual average relative humidity have been increasing, and the evaporation decreasing, showing a climate change tendency toward warm and wet, in which the temperature change is the most remarkable. The gray relation analysis between dynamic change of lakes and the meteorological factors shows that, the main reason of lake area and number increasing in Northern Tibetan Plateau over the past35years is the increase in ice and snow melting water under the temperature rise, increased precipitation, increased relative humidity and evaporation decreased.(4) Using the GIS space relevance tool, the northern plateau lakes change type was divided into five types:disappear, atrophic, stability, expansion and new, the analysis results showed that the number of new and expanding lake is much greater than the number of shrinking and disappear in each period, including is the most obvious expansion of stage in2000-2010.(5) Take the area as the dependent variable, the meteorological elements as the independent variable, to establish a multiple regression equation between meteorological elements and lake area, the correlation coefficient is0.73. The regression equation established through the meteorological elements and lake area that has significantly linear relationships, the model is capable of fitting the lake area of change. |
PDF Full Text Request