新疆植被覆盖变化及其对气候的敏感性分析

发布时间：2018-03-29 02:35

  本文选题：新疆地区　切入点：植被覆盖度　出处：《山东农业大学》2017年硕士论文

【摘要】：新疆地处欧亚大陆干旱半干旱气候区,区域内植被数量稀少,水土流失现象严重,生态环境极其脆弱。荒漠化导致了土地面积锐减、流动沙丘不断增加,土地生产力下降等一系列生态环境问题。以2002-2015年为研究时段,以新疆地区为研究区域,以年、季、月为研究尺度,利用52个气象站点数据、MODIS NDVI产品数据、社会经济统计数据以及野外观测资料等,采用均值法、MVC最大值合成法、回归分析、趋势分析、相关性分析法,揭示了植被覆盖变化时空特征及分布规律;在考虑多因子的基础上采取逐步综合的方法模拟降水量、气温的空间分布信息,剖析其时间序列变化趋势;从时空相关性的角度,运用空间计量分析和模型分析植被与气象因子的关系,并解释新疆地区植被覆盖变化的原因。结果表明:(1)新疆地区植被覆盖的空间分布规律为NDVI由西南向东北逐渐增加,与该区降水量分布相同;其中,裸土区的分布面积最大,稀疏植被区、较少植被区、适中植被区、茂密植被区、很密植被区面积依次减少;月尺度变化上,NDVI变化率4-6月2-4月6-8月;季节变化上,春、夏、秋季平均NDVI的线性趋势均为正值,春季平均NDVI最低,其次为秋季,夏季植被覆盖度最大;年际变化上,2002-2015年间,NDVI总体为上升趋势,2005-2009年间NDVI明显下降,2009年NDVI达到最低。(2)新疆年最大NDVI 14年间的变化趋势上,大部分地区植被覆盖均有增长的趋势,NDVI趋势率在-0.077-0.076之间,趋势不变的范围(-0.01Slope0.01)占94.99%,NDVI退化的范围(Slope-0.02)占10.35%,NDVI改善的范围(Slope0.02)占4.27%。(3)新疆地区多年平均降水量的地理分布总趋势是北多南少,西多东少,从西北向东南递减,大部分区域降水稀少(少于200mm),新疆年降水量呈现不明显减少的趋势;新疆降水量存在明显的季节差异,占全年降水量的比例:夏季春季秋季;新疆地区,降水量最大的月份为6月和7月,其次是8月,5月和9月;新疆地区多年平均气温在-3.5~15.7℃之间,区域年平均温度为9.36℃。总的地理分布特点是南高北低,西高东低,由南向北递减,新疆年平均气温呈显著增长趋势。新疆地区季节温度分配不均匀,夏季气温最高,其次为春季和秋季。冬季多年平均气温最低,严寒且漫长,平均温度在-10℃以下。(4)植被年最大NDVI值与年降水量存在较高的正相关性。从年际尺度上来看,年降水量变化是导致植被覆盖度变化的主要因素;年平均温度与年最大NDVI呈不显著正相关,表明随着温度的升高植被覆盖度也在升高,但是影响较小。
[Abstract]:Xinjiang is located in the arid and semi-arid climate area of Eurasia, with few vegetation, serious soil erosion and extremely fragile ecological environment. Desertification has resulted in a sharp decrease in land area and an increasing number of mobile sand dunes. A series of ecological and environmental problems, such as the decline of land productivity and so on, were studied in the period of 2002-2015, in Xinjiang region, in terms of year, season and month, and the data of 52 meteorological stations were used to produce MODIS NDVI data. The data of social and economic statistics and field observation were analyzed by means of MVC maximum value combination method, regression analysis, trend analysis and correlation analysis. The temporal and spatial characteristics and distribution law of vegetation cover change were revealed. On the basis of considering multiple factors, the paper adopts a step by step and comprehensive method to simulate the spatial distribution information of precipitation and temperature, and to analyze the trend of time series change; from the point of view of temporal and spatial correlation, The relationship between vegetation and meteorological factors was analyzed by using spatial econometric analysis and model, and the reason of vegetation cover change in Xinjiang was explained. The results showed that the spatial distribution of vegetation cover in Xinjiang increased gradually from southwest to northeast. The distribution of precipitation is the same as that in this area, in which the bare soil area is the largest, the sparse vegetation area, the less vegetation area, the moderate vegetation area, the dense vegetation area, and the very dense vegetation area decrease in turn. The linear trend of average NDVI in spring, summer and autumn was positive, the average NDVI in spring was the lowest in spring, followed by autumn, and the vegetation coverage in summer was the largest. From 2002 to 2015, the overall trend of NDVI was increasing. The NDVI decreased significantly in 2005-2009, and the NDVI reached the lowest in 2009.) in Xinjiang, the trend of annual maximum NDVI in 14 years was increased. The trend rate of vegetation cover in most areas was -0.077-0.076. The extent of NDVI degradation (Slope-0.02) and the range of NDVI improvement (Slope0.02) (4.27.2)) the general trend of the geographical distribution of the annual average precipitation in Xinjiang is that the north is more than the south, the west is less, the west is less, and the precipitation is less from the northwest to the southeast, and the distribution of the annual average precipitation in Xinjiang is smaller than that in the north and south, and less in the west and east, and decreases gradually from the northwest to the southeast. The precipitation in most regions is rare (less than 200mm-1), the annual precipitation in Xinjiang shows no obvious decreasing trend, the precipitation in Xinjiang has obvious seasonal differences, accounting for the proportion of precipitation in the whole year: summer, spring and autumn; Xinjiang, Xinjiang, Xinjiang, Xinjiang, Xinjiang, Xinjiang, Xinjiang, Xinjiang, China, The largest precipitation is in June and July, followed by August, May and September. The annual average temperature in Xinjiang is between -3.510 鈩，

本文编号：1679204