【作者】 徐利岗；

【导师】 周宏飞；

【作者基本信息】 石河子大学 ， 农业水土工程， 2008， 硕士

【摘要】 中国北方荒漠区主要位于西北内陆河流域、黄河流域及内蒙古高原的干旱、半干旱地区,分属新疆、青海、甘肃、内蒙古、宁夏、陕西、山西、河北等省和自治区,面积约340万平方公里,约占全国面积的35%。中国北方荒漠区降水稀少,时空分配极不均匀,不合理的土地资源利用导致生态与环境剧烈退化,是我国北方和东北亚地区的主要沙尘源地。生态与环境建设是该区实现社会经济可持续发展中面临的重大问题。研究荒漠区降水的时空变化特征及其变化趋势对荒漠地区退化生态系统植被的保护与恢复,区域社会经济与生态环境协调发展具有重要的指导意义。本论文利用我国北方荒漠区35个典型气象站1955年至2005年的月降水资料,对我国北方荒漠区降水分异规律及其丰枯变化趋势进行了深入分析;利用中国科学院阜康荒漠生态站设在新疆三工河流域的降雨量观测网2007年5—8月降雨资料,对西北内陆干旱区山地-绿洲-荒漠系统(MODS)降水的空间变异特征进行了分析。主要结论如下:1.在北方荒漠区降水时空变异方面,近50年来,我国北方荒漠区降水在时间和空间上均呈现出较大的变异性。预计未来,春、夏季降水将增多,冬季降水逐渐减少,年降水有增加趋势;降水年增幅较大的地区由内蒙古东部逐渐向西北偏移。存在5年、9年及准14年主周期,突变点分别位于1963、1988、1996和2001年;1988年以来降水以9年及14年周期为主。降水空间分布格局以“相间复杂”型和“东西相反”型(对北方荒漠区降水空间总体变化贡献率分别为35.8%和20.4%)为主,且新疆地区对北方荒漠区降水波动影响最大(对总体变化方差贡献为70.4%)。“相间复杂”型表征北方荒漠区受局部区域天气系统影响较大;“东西相反”型显示降水变化趋势自西向东依次减弱,西部有向暖湿变化中部地区趋于暖干而东部地区趋于干旱的可能。2.在北方荒漠区降水时空变化趋势方面,各地单独丰水年的概率要高于单独枯水年,而发生连枯年的概率则高于连丰年;极端干旱区和干旱区的降水有增加趋势的地区概率分别为83%和70 %,而半干旱地区降水有明显减少趋势的概率为58%。地处干旱区的新疆、青海及甘肃等地区降水将会增加,而地处半干旱区的内蒙古东部等地降水将会减少,降水年内分配的差异将变缓;北方荒漠区的西部和东部降水年际波动呈增加趋势,中部地区波动有变缓的趋势。变化范围在15%~78%之间,其中,新疆南部和青海的年际变化最大,大部分地区在变差系数40%以上,内蒙古地区相对平稳为28%左右。3.在内陆干旱区MODS的降水时空变异方面,应用EOF及REOF法、地统计学方法分析三工河流域雨量观测网数据。结果表明:依据0-30km、30-60km及60-150km处的三个荷载区段,与三工河流域山地、绿洲及荒漠等3个不同景观的地貌单元南北距离吻合;降水增幅自山地、绿洲、荒漠依次减小;山区降水变异函数符合高斯模型,绿洲区降水变异函数符合球状模型,荒漠区降水变异函数各月模型不同。在研究尺度下由随机因素引起的降水空间异质性仅占总空间异质性的0%-9.57%,以空间自相关引起的空间异质性为主。基于各地各时段基台值、分维数及变程等特征参数变化,判定绿洲区的降水空间变异性最大,山地次之,沙漠区最小;各地貌单元降雨的空间各向异性不显著。就全流域而言,6月份降水空间异质性最为显著,8月空间变化最小,这与变异系数相吻合;降雨在南北方向(0°)和东南-西北方向(135°)变异性最强。更多还原

【Abstract】 The desert region of northern China is mainly located in the northwest inland river basin, the Yellow River Basin and the Inner Mongolia plateau ,where are the arid and semi-arid areas. Political district belongs to Xinjiang,Qinghai, Gansu, Inner Mongolia, Ningxia, Shaanxi, Shanxi and Hebei. The area is about 3.4 million square kilometers, accounting for 35% of the China. The precipitation is lack and uneven for the temporal and spatial distribution in the desert region of northern China. Unsuitable water and land resources exploitation led to ecological and environmental degradation sharply in this regions, which also is the main dust source of the northern China and the northeast Asian. The ecological and environmental construction are the major problems of the socio-economic sustainable development in this regions. Research on spatial and temporal variability of precipitation characteristics and trend in desert region have an important guiding significance, which can protection and restoration the vegetation of desertification and degraded ecosystem, promote regional socio- economic and ecological environment harmonious development.Spatial variability rule of precipitation and its trends of rich and lack are analysed in this paper by the monthly precipitation data of 35 national meteorological observation sites in the desert region of northern China during 1951- 2005. The temporal and spatial variability characteristics of the precipitation are discussed for the mountain-oasis-desert system (MODS) in arid region of northwest inland watershed,based on the observation data from the precipitation observation network located in the San-gong River watershed and established by Fukang National Desert Ecosystem Research Station,Chinese Academy of Sciences. Main results indicate as below:1. Spatial and temporal variability of precipitation in the desert region of northern China. In recent 50 years, the precipitation has greater variability both in spatial and temporal. It is estimated that the precipitation will increase in spring and summer season, and will decrease in winter sesson in future. Annual precipitation is increase in general. The areas which have bigger annual increased amplitude will move from east of the Inner Mongolia Plateau to northwest of China.There are 5a, 9a and 14a main-cycle, and the abrupt precipitation changes were observed in 1963、1988、1996 and 2000. Precipitation primarily controlled by 9a and 14a cycle since 1988. Precipitation spatial distribution pattern is primarily " complex type " and "west-east type " (to contribution the overall changes rates were 35.8% and 20.4%). Xinjiang is the best affected region for the precipitation fluctuations of the northern desert region (contribution to 70.4% of all fluctuations). The region characterized by " Complex type " has a greater impact by the local weather systems. " West-east type " shows that precipitation fluctuation trends were weakened from west to east. It is possible that the west region will bacome warmer and weter, the central region will bacome warmer and drier, but the eastern region will get drought.2.The trends for spatial and temporal variability of precipitation in the desert region of northern China. The probability of single abundant precipitation year is higher than single short precipitation year and the continuous short precipitation year is higher than continuous abundant precipitation year. In extreme arid regions and arid regions, such as Xinjiang,Qinhai and Gansu, the probability of precipitation increasing are 83% and 70 % respectively.On the contrary, in semi-arid regions,like Inn Mongolia, the probability of precipitation decreasing is 58%, the variability will change slowly for the distribution of intra-annual precipitation . The inter-annual precipitation variability has increasing trend in the western and eastern part of the northern desert region, but the central region change slowly, the scope is 15% to 78%, especially in south of Xinjiang and Qinghai, the inter-annual change is the biggest.In most regions, variation coefficient is more than 40%.The Inner Mongolia region is stable comparatively, about 28%.3.The precipitation spatial variation of MODS in inland river watershed. Based on the empirical orthogonal function (EOF) ,rotated empirical orthogonal function (REOF) and geostatistics methods, the precipitation observation network data of the San-gong River Watershed are analysed. The results showed that: based on the 0-30 km ,30-60km and 60-150 km of the three loads section, the watershed can be divided into three landscape units: mountain, oasis and desert. Precipitation increasing trend become smaller and smaller from mountain, oasis to desert. The mountain precipitation semivariogram accord gaussian model, the oasis precipitation semivariogram accord spherical model, the desert precipitation semivariogram model is different in each month .In research scale, owing to the random factors arising precipitation spatial heterogeneity occupy 0% -9.57% of all, so the spatial heterogeneity of spatial was mainly caused by autocorrelation. Based on all parts and periods of characteristic parameter, such as sill, fractal dimension and separation distance, it is judged that the biggest spatial variation of precipitation is in oasis,followed by mountain, desert area is minimum.The precipitation spatial aeolotropy is not remarkable in each landscape unit. For the whole watershed, precipitation spatial heterogeneity are the most significant in June, and the smallest in August, which coincides with the coefficient of variation.The precipitation variability in the north-south direction (0°) and the southeast-northwest (135°) are strongest.更多还原