Research On Climate Effect Of Earth-atmosphere Water Vapor Exchange And Transport In The Three-river Source Area

The strong uplift of qinghai-tibet plateau makes itself into the cryosphere, formed the unique alpine environment, developed glaciers, alpine wetland,natural alpine lakes and reservoirs, and as the "water tower of the world" gave birth to the great rivers of the world famous.The three-river source area of the plateau hinterland, is the source of Yangtze river, Yellow River and the lancang river, contributing to the region one thousand years with a steady stream of fresh water resources.Plateau surface soil-vegetation-atmosphere interaction process in the energy and water cycle plays a very important role, its change profoundly affects the subsequent monsoon behavior and process of the global climate.Because of its special geographical position and the surface of heating effect, the Three river source aear become the center of large pump "plateau", by "pumping" warm moist air flows from southwest in the formation of abundant precipitation, for the Yangtze river, Yellow River and lancang river originating provides a rich source of water.This article mainly from the three river source aera climate change characteristics, alpine wetland evapotranspiration,and the source area of water vapor sources in three aspects, analysis of water circulation mechanism.1)18meteorological stations data from1961to2012were used to analyze the meteorological parameters which reflects air water resource in the Three-river source area.We discussed the temporal and spatial distribution of these meteorological parameters, like temperature, precipitation, relative humidity, evaporation. In addition,variation of ecological vegetation environment,glaciers,lakes and runoff were analyzed in the Three-river source area.2) By observation of micro-meteorological characteristics in Yushu Longbaotan wetland in the Three-river source area,we analyzed the influence of meteorological parameters to evapotranspiration characteristics in degraded alpine wetland.3) Using a three-dimensional Lagrange back track mode FLEXPART simulated water vapor source arrived in the three-river source area in summer from2007to2009.And analyzed the potential water vapor source area and its transmission path.The main research results summarized as follows:1) Analysis of the meteorological parameter’s spatial variation reflects the average temperature and precipitation were increased,but relative humidity, evaporation and cloud cover were appeared a downward trend.The series of climate change may cause the plateau continue warming, strengthen the surface retain water and drop the air water resource et al.At the same time, climate change provides certain advantages for the ground vegetation growth, but climate change is a complex process on the plateau, needs further research.2)At first, it is outstanding the diurnal and seasonal variation of potential evapotranspiration; Actual evapotranspiration appeared winter small and summer larger, and summer contribute the most of evapotranspiration.Evapotranspiration was more larger than rainfall and water loss was serious, local evapotranspiration contribute amount to precipitation during observation.Soil temperature has significant effects on evapotranspiration, especially the5cm soil temperature has a well relationship with it. Soil humidity provide enough water for evapotranspiration. Temperature is the main factor effects the evapotranspiration in annual. However, the alpine wetland degradation of actual evaporation and radiation have almost the same change trend, the temperature has little effect on evapotranspiration, evaporation and relative humidity appear significant inverse relationship in a sunny day.3)First of all, the main evaporation source area effects the three-river source area is distributed in the central Asian region of northwest edge of three-river source area. The water vapor from the Indian Ocean is very abundant, but most do not climb the Tibetan Plateau, and loss in the south of plateau. Second, the water vapor path which influence the summer precipitation of the three-river source area are mainly two path. The first along the east coast to the African continent the Arabian sea transport across the equator reach India, and the push to toward the north plateau. The second was from central Asia and west Asia transport to the Three-river source area.Finally, a quantitative analysis of water vapor transport of the summer months, determines the influence of three-river area dominant water vapor source of water vapor. The west of Tibetan Plateau was the main source area and north of the plateau was the second during June. The Arabian sea became the main source area and northe of plateau was the second during July. In August, the Arabian sea contribution to source area was reduced, and north of plateau was stable, increased over the bay of Bengal, contribution of the west side of plateau was little.