Knowledge Resource Center for Ecological Environment in Arid Area
| 新疆地区植被覆盖时空格局及其区域响应 | |
| 其他题名 | Spatio-temporal Pattern of Vegetation and Its Regional Response in Xinjiang Region |
| 杜自强 | |
| 出版年 | 2012 |
| 学位类型 | 博士 |
| 导师 | 王建 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 摘要：近几十年来，全球变化与人类活动对区域环境在土地利用/覆被、地表过程、植被分布等方面产生了显著影响。植被是联结土壤、大气和水分的自然“纽带”，在全球变化研究中起到“指示器”的作用，植被覆盖时空格局变化是自然和人类活动长期交互作用的结果，并具有明显的时空分异特征。运用遥感数据和方法在大、中尺度下分析植被动态及与气候、人类活动的响应关系具有显著优势，己成为一个重要领域。\n新疆以深居内陆的地理区位、干旱的大陆性气候、山盆相间的地貌格局、广泛发育的内陆流域以及荒漠性的土壤植被与我国东部季风区和青藏高寒区形成鲜明的对比，同时在全球干旱区类型中也独具特色，形成了典型的山地—绿洲—荒漠系统（MODS， mountain-oasis-desert system），成为研究干旱生态与地理、资源与环境以及社会与经济问题的天然实验室。\n本文以全球变化背景下西北干旱区生态系统变化与区域响应为出发点，选择新疆地区的地表植被覆盖为研究对象，利用长时间序列的遥感资料、多年气象数据和社会经济统计数据，动态监测和模拟区域植被生长变化的时空格局及其对气候变化和人类活动的响应机制，以期为进一步探讨该地区植被覆盖与气候变化、人类活动的关系，合理调节人类活动提供一些现实依据。\n以GIMMS AVHRR NDVI为主要数据源，采用S-G平滑滤波和最大化合成方法重建研究区逐年、逐季、逐月的NDVI时间序列数据。在从植被NDVI数量和质量两个方面分析植被总体变化特征的基础上，采用重心理论和模型、空间地统计方法、线性回归分析和相关系数趋势检验法分析了新疆过去近30a植被覆盖的时空格局和演变趋势。研究表明：从80年代至今，新疆地区植被总量一直处于增长的态势，但每年的植被都是以低覆盖类型植被为主；夏季和秋季植被平均NDVI上升最快的时期，这两个季节植被状况基本决定了新疆全年的植被分布状况。新疆植被的整体分布格局与我国植被正好相反，NDVI大体上呈现由西北向东南递减的趋势。从植被重心移动区位来看，植被重心一直在北疆区域、大致在伊犁哈萨克自治州新源县和巴州的和静县境内移动；从移动方向来看，植被重心在东北、西北、西南、东南各个方向上都有移动，但其变动状况主要集中在东北方向；从移动距离来看，植被移动幅度一直处于“增大——减小”交替进行之中。NDVI的空间分布在全局范围内呈现正的相关性，不同方向的植被分布具有相异的空间格局；总的看来，随机性因子的影响较弱，结构性因子的影响占据绝对控制地位；NDVI空间分布与地理环境要素密切相关，在空间上呈现一定的分布规律，东西和东北-西南方向上呈现较大的、正的空间自相关，在南北和西北-东西南方向上则呈现负的空间自相关。过去近30a，虽然在部分地区植被呈现恶化态势，但是在更大的范围上植被覆盖状况还是在不断改善的。全疆植被呈现增加趋势的比例大于降低趋势的比例，多年的植被变化以植被增加趋势为主。\n对植被变化的驱动因素总体理论分析的基础上，利用GIMMS NDVI遥感资料，结合气候、社会经济统计数据，运用主成分分析和逐步回归等分析方法，从自然环境、社会经济发展、科技进步等不同视角，系统地研究植被覆盖变化的驱动力，构建植被覆盖变化的驱动力模型。研究表明：新疆地区植被的动态变化是驱动力系统运动的结果，地理位置、气候条件、地形地貌、土壤条件、水文条件和人类的社会经济活动都会对植被分布和植被覆盖变化产生不同程度的影响。植被覆盖主要是经济发展水平、人们的生活水平和气候因素的正向作用以及畜牧业发展的逆向作用综合因素影响的结果。其中，人文因素综合驱动力对植被覆盖变化的作用效果明显于自然因素。从分析结果看，这样的方法得出的结论从理论上能够解释的通，比较符合当地实际。\n利用70多个气象站点的月平均气象资料，采用距平分析和线性趋势分析、相关分析、时滞分析等方法，分析过去近30a新疆各区域气候变化总体特征及其气候变化的响应关系。研究表明：在以气候变暖为主要特征的全球变化背景下，新疆地区年平均气温呈现较为明显的上升趋势，年降水量呈现波动式的增长趋势，总体上气候朝向暖湿化发展，但各区域的气候变化表现出了明显的时空变化和区域分异特征。从植被生长周期来看，新疆地区植被与气温和降水均有较好的相关性，气温在各类植被生长中对植被短时的影响较大，但植被对气候因子的响应存在空间差异。不同类型植被与同期的温度、降水均具有高度的相关性，但不同类型植被对温度与降水的响应类型有所不同：对于温度的响应程度由高到低为草甸、草原、人工植被、荒漠、沼泽；对于降水的响应程度由高到低为草甸、荒漠、草原、沼泽、人工植被；各类型植被对同期气温的相关程度均好于降水。总体上，植被对气温和降水变化的响应都存在一定时间段的滞后效应，而且降水一般以时滞两个月为主，气温一般以时滞一个月为主；植被对前期降水和对同期气温的响应程度较为明显。但不同气候区域的植被以及不同类型的植被对气候因子在响应程度和响应时效方面也表现出鲜明的分异规律。\n选择NDVI作为衡量植被覆盖变化过程中气候变化和人类活动相对作用的公共指标，分析植被覆盖变化过程中气候变化和人为活动相对作用，特别讨论植被覆盖变化对人类活动作用响应的时空格局。研究表明：在人为因素影响下，过去近30a新疆植被覆盖面积呈现增加态势，这种情况基本上和当地实际相符合，说明人为活动在改善生态环境方面的起到了一定的作用。人为因素是植被NDVI变化的双刃剑，对植被的改善和抑制作用同时存在。新疆地区多年来植被的改善与人为影响密切相关，而植被NDVI的降低与人类活动的作用之间没有表现出明显的相关关系。80年代以来人类活动对植被起到了一定程度的改善作用，但普遍来说逆向干扰的影响范围（区域）比正向作用的影响范围（区域）要大。植被覆盖对人为因素的响应具有空间异质性，人为促使植被呈现明显增加态势的地区主要集中在南疆的绿洲地带、天山北坡绿洲地带以及巴里坤山地草原一带；植被NDVI残差呈现减少态势明显的地区主要集中在北疆西北部的塔城地区。\n关键词：植被变化； 时空格局； 区域响应； 驱动力； 人为影响 |
| 英文摘要 | Abstract：In recent decades, global change and human activities have significant impacts on the regional environment in land use / land cover, surface processes, vegetation distribution, etc. The spatio-temporal patterns of vegetation cover change are the results of the interaction between natural factors and human activities for long terms, and these changes are identified by different regional characteristics. The analysis of vegetation dynamics and its response relationship with climate and human activities in large, medium-scale with remote-sensed and GIS methods are becoming an important area in global change research.\nXinjiang Region is the characteristic of secluded-inland geographic location, arid continental climate, mountain landscape pattern, extensive development of the inland valley and desert vegetation and soils. These are clear differences with the eastern monsoon regions and Tibet alpine zone. Xinjiang Region is also unique with its mountain-oasis-desert system among the arid regions in the world. Xinjiang Region, therefore, is becoming a natural laboratory for the study of arid ecology and geography, resources and environment and social as well as economic problems because the all elements above mentioned.\nThis thesis has made the ecosystem changes and its regional responses in the context of global change a focus of attention. The thesis has monitored dynamically vegetationchange for ages and simulated the response of vegetation to human activities and climatechange with long time series ofremote-sensed data, meteorological dataand socio-economicstatisticaldata. Our primary aim is to achieve the relationship between vegetation coverage and climate change and human activities, simultaneously, to provide some realistic basis for adjusting reasonably human activities.\nThe time series remote-sensed data by years, quarter and months have been reconstructed by S-G smoothing filter and MVC methods. The feature on vegetation variation is described from the aspects of its qualities and quantities. The spatio-temporal patterns of vegetation variation and its change tendencies for thirty ages are depicted by gravity centre model, geo-statistics, regression analysis and correlation coefficient method. The results are as follows:\nThe vegetation is increasing for years in Xinjiang Region. However, the annualvegetationisdominatedby lowvegetationcover. The natural growth of vegetation is rising at high speed in summer and autumn. Hence, the two seasons basically influence the distribution of vegetation in a whole year. The overall distribution pattern of the vegetation of Xinjiang is contrary to that in other regions of China. NDVI generally shows decreasing trend from northwest to southeast.\nThe gravity center of vegetation is constantly in motion in North Xinjiang from the gravity location point of view. it is movingin alldirections, but thesituationchangesmainly in thenortheast from themoving directionof view, and it has been in therange of "increasing or decreasing "movement by turnsfrom thedistance point of view.\nThe spatial distribution ofNDVIin the global scopeshowsa positivecorrelation among them as well as differentspatial patterns with different directions. Overall,the impact ofrandomfactorsis weak and the impact ofstructuralfactorsaccounts forthe absolutecontrol. The spatial distribution of NDVI is closely related to thegeographical environment. The positivespatial autocorrelation is in thenorth-south andnortheast-southwest, and thenegative spatial autocorrelation is in the north-south and northwest-southeast.\nThe prevalence of NDVI is increasing, although thevegetationhas become progressively worsein some areas, an upward trend in vegetational variation is evidently ona larger scale. \nBased on theoretical analysis of driversofvegetation change, the thesis buildsthe drivingforce modeland gives a detailstudy on drivers of change inthe vegetationcover using GIMMS NDVI data, climate and socio-economic statistical data. The analysis is accomplished by principal componentand stepwiseregressionmethods from the perspective of naturalenvironment, social and economic development, variousscientific and technological progresses in agriculture.The results are as follows:\nThe dynamics of vegetation in Xinjiang is the interaction of various driving forces. All kinds of driving elements have different impacts on vegetation cover change, such as geographical location, climatic conditions, topography, soil conditions, hydrological conditions and socio-economic activities. A positive effect on vegetation variation comes from economic development, living standards and climatic factors and an adverse effect rise from the development of animal husbandry. The driving impacts of human activities are more significantly powerful than natural elements. \nThe characteristics ofclimate changein recent thirty years and the response relationship of vegetation to climate change are elucidated with the monthlyaverageweather data of more than 70 meteorological stations. The linear trend, anomalyanalysis, correlation analysis and time-delayedanalysis methods are employed. The results are as follows:\nThe annual average temperature shows an obviously upward trend, and annual precipitation fluctuates ascending in the background of global change with climate warming. The tendency of warm and humid climate is more obviously all in all, but the region climate change shows a clear temporal-spatial variation and regional differentiation.\nThe relation of vegetation to temperature and precipitation is closed, and temperature has a greater impact on the vegetation in month scale. The response of vegetation to climate factors exists spatial differences. \nDifferent types of vegetation are highly relevant with temperature and precipitation, and different type’s responses of vegetation to climate are different. The response of vegetation to temperature is in order of: meadow>steppe>artificial vegetation>deserta>swamp; the response of vegetation to temperature is in order of: meadow>deserta>steppe>swamp> artificial vegetation. \nOverall, the response of vegetation to temperature and precipitation has a certain time-lag effect. The effect of precipitation to vegetation lag two months generally, the influence of temperature is generally dominated by one-month lag. The vegetation in different climatic regions and different type brings a distinct differentiation.\nFinally, NDVI is used a common indicator to discern the relative role of human activities and climate change on vegetation variation. In particular, the spatio-temporal response of vegetation to human activities is discussed. The results are as follows:\nThe vegetation coverage was increasing in the past thirty years under the influence of human factors. The human activities have improved vegetation coverage. The human factors have an improvement and inhibition in vegetation growth just like a double-edged sword. The vegetation improved is significantly relevant to human activities, and there is not too much interference from human factors to induce the shrink of vegetation. \nHuman activities have played an important role in a certain improvement of vegetation change since the 1980s, and the areas suffered from adverse effects of human activities are a little larger than those by positive-going effects. The response of vegetation to human factors shows some spatial heterogeneity. The vegetation in oasis area of southern Xinjiang, northern Tianshan mountain and Barkol grassland area has shown a significant increase, and the decreasing trend of NDVI residuals is mainly concentrated in Tacheng, the northwest of Northern Xinjiang.\nKeywords：Vegetation variation; Spatio-temporal pattern; Regional response; Driving force; Human-induced influence |
| 中文关键词 | 植被变化 ; 时空格局 ; 区域响应 ; 驱动力 ; 人为影响 |
| 英文关键词 | Vegetation variation Spatio-temporal pattern Regional response Driving force Human-induced influence |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 地图学与地理信息系统 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287032 |
| 推荐引用方式 GB/T 7714 | 杜自强. 新疆地区植被覆盖时空格局及其区域响应[D]. 中国科学院大学,2012. |
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