| Climate is one of the most important components in the environment that human being lives, its any changes of environment may have a great impact on both the natural ecological system and the socio-economic, therefore to understand the mechanism of climate change and copeing with the climate change and its effect on the environment is not only a significant scientific issue, but also an environmental, economic, political and even national security issue. Previous researches show that climate in northwest China has been undergoing an obvious change associate with the global warming in the recent years. The northwest China is a vast territory in which there is a very complicated landforms and biodiversity, meanwhile it is controlled by westerlies and the East Asian monsoon. In Northwest China the seasonal, annual and diurnal variation of the climatic component is so distinct that there are also many different kinds of meteorological disasters that threaten the local people's life and property. But the spatial distribution of the current meteorological stations in this region are not managed compatible. Due to three main reasons: the first one is that most of current meteorological stations are based on County-level administrative divisions without considering of the representative about the weather and the climate patterns, the second reason is that number of the meteorological station which is too less to cover all the ecological system, the last one is that the low temporal resolution meteorological observation couldn't show the character of the climatic process.The key purpose of this thesis is trying to further investigate the forming mechanisms of the regional climate change, improve the ability of monitoring and forecasting the meteorological disaster in the drainage basin, and finally monitor the regional response mechanism and rule of the arid climate change in the Northwestern Region under the global climate change background. To achieve this objective, we choose the Xiying river basin, which is a branch of the Shiyang River drainge located at the east section of the eastern Qilian mountain as our representational reaserch area .we have got some preliminary conclusions through detailed research about the regional mountain climate:1, We have set three field automatic weather stations in the mountain desert steppe zone, the cold-temperature coniferous forest zone and the Alpine rhododendron shrub zone respectively in the Xiying river basin. Combining with the existing general weather stations, we have formed more perfect meteorological observational network compared with the previous shortage of the mountain meteorological observation stations in this area. This could offer essential date for the research of the long time series of climate change in this area.2.Through analyzing the meteorological data we discovered that: the annual precipitation enhances along with the increasing of the altitude, the largest precipitation belt is mainly in the cold warm coniferous forest vegetation area at about 2714m, and the precipitation mainly concentrates in June, July, August and September all the year round; The solar radiation received by the ground (start at 7:00 and finish at 20:00) has a reduced tendency as the increasing of the altitude owing to the influence of the fog weather, and the radiation reaches is minimum at the region where the precipitation gets to its maximum, the solar radiation received by the ground gets to is maximum in May all the year round, at about 13:00 all the day; The temperature vertical lapse-rate is smaller than 0.65℃/100 m in the winter, and bigger in the summer, the temperature is highest at 14;00-15:00 in one day and lowest at 7:00-8:00; Influenced by precipitation, and temperature etc, the vapor tension reduce along with the increase of the altitude, the vapor tension is highest in August, the soil moisture content is highest in May, July, September or in October; the relative humidity enhances along with the increase of the altitude, and is biggest in March and August to September in one year; The diurnal variation of the relative humidity and the content of soil moisture assumes the font "V"; The maximum wind speed is biggest in April to May in one year.3. By analysis of the data of monthly and annual temperature and precipitation observed by the meteorological stations in the eastern section of the Qilian Mountains with theirs elevations and geographical coordinates, the author suggested the following mathematical expressions of the geospatial change of both all-year precipitation and annual temperature in Xiying river basin:Where P represents the annual precipitation, T Trepresents the mean annual temperature ameliorated with topography based on the mean annual temperature simulated by conventional statistical model, TH represents the mean annual temperature simulated by conventional statistical model, Y represents the latitudinal coordinator, H represents the elevation of meteorological station,α5 represents the mean of the slope in a radius of five kilometers, e represents the max of the slope in a radius of one kilometer, (?)n the max of the aspect in a radius of one kilometer. The author found the precipitation increases with the increase of the altitude and the slope, and with the decrease of the latitude. The author also found that the temperature decreases with the increase of the altitude and the latitudinal coordinator, at one time, the solar radiation received by the ground is different because of the relief, so the ameliorated temperature model is more virtual.4. Synthesizing the weather data analysis and the distributional model of the precipitation, we discovered that there are two biggest precipitation belts in the Xiying river basin, one locates in the cold-temperature coniferous forest vegetation areas at the altitude of about2700m, the other locates at the summit of LengLongling, we assume that the precipitation at the higher maximum belt is possibly the original vapor supply of the present ice volume at the summit.
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