【作者】 王小莉；

【导师】 潘保田；

【作者基本信息】 兰州大学 ， 自然地理学， 2008， 硕士

【摘要】 气候作为人类赖以生存的自然环境的一个重要组成部分，它的任何变化都会对自然生态系统以及社会经济产生不可忽视的影响。那么如何认识气候变化?如何应对气候变化及其对环境的影响?这不仅仅是科学的前沿问题，也是环境问题、经济问题、政治问题和国家安全问题。近年来的研究表明，在全球变暖背景下，我国西北地区气候正悄然发生着变化。但是，西北地区地域辽阔，区域内地形地貌复杂，生态系统多样，同时受西风带、东亚季风的共同影响，气候要素的季节变化、年际变化和日变化十分明显，气象灾害种类繁多，直接威胁到人民财产安全。由于目前该区站网空间分布不尽合理，现有气象部门站网主要以县级行政区划为基点，没有充分考虑其对天气、气候的代表性；站网空间分辨率低，对生态类型的覆盖不足：时间分辨率过低，无法分辨天气过程的特征。为了深刻认识区域天气气候变化的形成机理，提高流域气象灾害监测预警能力，监测全球气候变化背景下西北地区干旱气候变化的区域响应机制和规律，我们选择祁连山东段石羊河水系的支流西营河流域为代表，依托近期建设的气象观测台站，对该区山地气候进行详细的研究，初步结论如下：1、在西营河流域内的山地荒漠草原带、寒温性针叶林带、高寒杜鹃灌丛带三个植被区分别建立了野外自动气象观测站，结合已有的常规气象观测站，形成了较为完善的气象观测网，从而补充了该区山地气象观测站点建设的不足，为研究该区长时间序列的气候变化提供基础数据。2、通过对气象数据的分析发现，年降水量随海拔高度的升高而增加，且在2714m左右的寒温性针叶林植被区存在一个最大降水高度带，一年中降水主要集中于6、7、8、9月份；地面接收的太阳辐射量(7时开始接收20时结束)由于受云雾天气的影响，随海拔高度的升高有减少的趋势，且在降水量最多的地带其值最少，年分配中为5月份其值最多，一天内13时左右接受的太阳辐射量最多；气温垂直递减率冬半年小于0．65℃／100m，夏半年则大于该值，一日中14-15时气温最高，7-8时最低；由于受降水和气温等因素的影响，水汽压随海拔高度升高而降低，水汽压8月份最高，土壤水分含量三个不同的站点在5、7、9或10月份最高，相对湿度随海拔高度升高而增大，且在一年内3月和8-9月份最大；相对湿度和土壤水分含量在日内变化呈“V”字型；最大风速一年内在春季4-5月份最大，最大值可达12．35m／s，一天内风速在14-15时最大，并且风向在夜间至12时风速较小时，主要以西南风为主，白天风速较大时，主要以东北风为主，与西营河谷走向相一致。3、本文以地理信息系统为基本手段，同时利用多元统计回归的方法结合散点图分析了气温和降水与地理空间位置和海拔高度之间的关系，寻求较佳的回归方程以表示气温降水空间分布的结构分量特征。研究发现，在西营河流域降水不仅仅与海拔高度有关，还与坡度存在一定的关系，可能是由于在山区地形雨在降水中占有相当比例，坡度大小影响地形抬升的强度，得到全年降水总量的分布式模型关系式为：P=a+b*lnY+c*H+d*α5。对于气温，进一步考虑太阳辐射在山地的分布，对气温的传统分布式模型进行改进，获得了较好的效果，最后得到年均气温的分布式模型关系式为：T_T=T_H-|T_H|*[1-(cose-sinecosφ_n)]，T_H=a+b*H+c*lnY。4、综合气象数据分析显示的降水的鲜明季节变化，各季最大降水高度的不同及降水的分布式模型，我们推断在西营河流域存在两个最大降水高度带，一个位于海拔高度在2700m左右的寒温性针叶林植被区，一个位于山顶冷龙岭，这也可能是山顶现代冰川发育的物质来源。更多还原

【Abstract】 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, T_H 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.更多还原