【作者】 陈志云；

【导师】 林学钰；

【作者基本信息】 吉林大学 ， 水文学及水资源， 2012， 博士

【摘要】 植被是陆地生态系统的重要组成部分，是生态系统中物质循环与能量流动的中枢，对人类社会经济活动有重要贡献。在干旱半干旱地区，植被是生态环境好坏的参照物，植被生长状态与土壤水分状况和地下水状态有直接关系。研究干旱地区植被生长与地下水之间的依存关系，对合理利用水资源，改善区域生态环境具有非常重要的意义。定量研究干旱地区植物生长与地下水位埋深的关系，不仅可以为植被生态系统的可持续维持，而且可以为退化植被生态系统的恢复重建提供科学依据，从而为我国广大干旱区实现经济、社会和生态环境协调可持续发展提供决策依据。近年来，随着遥感技术的发展，遥感数据以其数据量大、覆盖范围广、时间序列性强等优势，已经被广泛应用于大尺度的生态环境研究中。将遥感与地下水信息相结合，可以在宏观尺度上定量研究地下水与植被之间的相互作用。西辽河流域地处东北平原西部农牧交错带的东缘，是全球变化的敏感区，也是国家实施西部大开发战略的重点地区之一。本论文首先通过对气象、水文、地下水水位埋深等资料的统计和评价，确定了研究区的地下水动态类型，并根据实际情况将研究区分成降水入渗型、降水入渗开采型、降水入渗蒸发型、降水入渗径流型四个地下水动态类型，然后采用数理统计方法和GIS空间分析技术，结合遥感数据，进行了西辽河平原植被覆盖度与地下水位埋深之间关系的挖掘研究。通过以上研究，本文得到以下结论：（1）西辽河平原地区的地下水位埋深受人为开采影响较大，在内蒙古自治区通辽市科尔沁区、科尔沁左翼后旗以及奈曼旗的中部等地下水集中开采的地区出现较明显的降落漏斗。（2）本文利用1989、1994、1999、2006、2010年的Landsat-5影像（TM、ETM+影像），运用GIS和RS技术，基于宏观以及微观尺度对西辽河流域的植被信息进行了提取。其中宏观尺度方面，分别采用植被指数及监督分类方法进行植被信息提取。采用归一化植被指数（NDVI），对西辽河5个时期植被覆盖的变化情况进行了分析，结果表明，100m是最适合植被生长的高程值；5个时期西辽河流域植被覆盖度均值变化情况是1989>2010>2006>1999>1994。采用监督分类中的最大似然法对植被进行分类，最终得到耕地、草地、林地这三种植被类型的年际变化情况是：从1989年到2010年，耕地、草地的面积都在不断增大，而林地总体趋势是减少。在微观尺度上，利用野外考察采集到的植被光谱信息，基于面向对象的方法，将草地进一步提取为中生偏旱与中生偏湿两类，结果表明，研究区中生偏旱草地的总面积明显大于中生偏湿草地的总面积；在分类精度上较监督分类有所提高。（3）研究区植被覆盖度受地貌类型影响，在微起伏平地、河漫滩及黄土台地等地势平坦、河水补给较好的地貌地区，植被长势普遍较好，在沙丘、沙地及坡洪积扇等干旱、地下水补给较少的地区，植被覆盖度明显下降。（4）研究区植被覆盖度受降雨影响较为显著，尤其在沙地区域具有明显的相关性，呈正相关，相关系数为0.76，植被覆盖度值随降水量的增大而增大。（5）研究区地下水位埋深与植被生态具有一定的响应关系，结合地下水位埋深与植被覆盖度均值研究发现，在西辽河平原草地区，地下水位埋深平均值小于4m时，对植被覆盖度有明显的影响，当埋深在0.5-2.7m之间时较适宜草地植被生长，而当地下水位埋深大于4m时，埋深对草地地区的植被不再为主要的影响因素。本论文的创新点：1）采用GIS空间分析技术，进行了西辽河平原植被覆盖度与地下水位埋深之间关系的挖掘研究。2）在对西辽河平原地下水动态与植被宏观变化响应关系分析的基础上，采用数理统计和空间分析技术相结合的方法，首次对研究区的植被演化趋势进行了预测分析。更多还原

【Abstract】 Vegetation is an important part of terrestrial ecosystem and the centrum of the materialcirculation and energy flow in ecosystem. It devotes an important contribution to humansocial and economic activities. Vegetation shows the status of the ecological environment inarid and semi-arid areas. Vegetation status is connected with soil moisture and groundwaterlevel. The research on the relationship between vegetation growth and groundwater in aridarea has great significance on the rational use of water resources and improvement of theregional ecological environment. Quantitative description on the relationship between plantgrowth and groundwater depth in arid regions can provide foundation of science not only forthe sustainable maintenance of the vegetation ecosystems, but also for the restoration andregeneration of the degraded vegetation ecosystem. Therefore it will providedecision-making basis for achieving the coordinated and sustainable development ofeconomic, social and ecological environment in the arid areas of our country. Remotesensing data have been used widely in large-scale ecological environment research in recentyears with the development of remote sensing technology. The interaction betweengroundwater and vegetation can be studied quantitatively on macroscopic scale by usingcombination of remote sensing and groundwater information.West Liao River Basin is located in the east edge of west part of Northeast Plain which isacetones of farmland and pasture. It is a sensitive area of global climate change, and also oneof the key areas of national western development strategy implementation. Firstly, thedynamic type of groundwater in research area will be determined in this paper by statisticand evaluation on meteorological, hydrological, groundwater depth etc. data. The dynamictype of groundwater will be divided into four types, including precipitation infiltration,precipitation infiltration mining, precipitation infiltration and evaporation, and precipitationinfiltration runoff according to the actual situation. Then, the further research on therelationship between vegetation coverage and groundwater depth in West Liao River Plainwill be completed by mathematical and statistical methods, GIS spatial analysis techniquescombining with remote sensing data. The following conclusions will be achieved through the research.(1) The groundwater depth of West Liao River Plain is affected significantly by artificialexploitation. The evident groundwater drawdown funnel has appeared on regions where thegroundwater is concentrative exploited,such as Horqin District of Tongliao City, HorqinZuoyi Hou Banner and middle area of Naiman Banner in Inner Mongolian AutonomousRegion.(2) The vegetation information of West Liao River Basin will be extracted based on themacroscopic and microscopic scale by using GIS and RS technology, and Landsat-5 images（TM、ETM+ images）in 1989, 1994, 1999, 2006 and 2010.The vegetation index and supervised classification methods will be used for informationextraction in the macroscopic scale. The change of vegetation coverage of West Liao Riverin above five periods will be analyzed by Normalized Difference Vegetation Index (NDVI)method. The analysis shows that 100m is the most suitable elevation value for vegetationgrowth. The change of average vegetation coverage rate of West Liao River Basin in the fiveperiods is 1989>2010>2006>1999>1994. The actual change conclusion of arable land,grassland and woodland will be obtained by using maximum likelihood method of thesupervised classification. The conlusion is that the arable land and grassland area isincreasing and the overall trend of the woodland is reducing from 1989 to 2010.The grassland will be further divided into two types, including partial drought and partialwet based on the methods of analyzing specific samples and utilizing the vegetation spectralinformation collected from fieldwork in the microscopic scale part,. The result shows partialdrought grass area is larger obviously than the partial wet grass area in the research region,and the classification accuracy is also better than the supervised classification.(3) The vegetation coverage is affected by the types of terrain in research region. Generally,the vegetation coverage is good in the flat terrain, such as slight undulate plain, flood plainand loess tableland. The vegetation coverage is decreased in arid area and the area with poorgroundwater supplement, such as sand dunes, sand ground, and the slope of alluvial fan, etc.(4) The vegetation coverage is affected significantly by precipitation in research region.Specially, the clear positive correlation will be obtained in the sandy area. The correlationcoefficient is 0.76. The vegetation coverage is better with more rainfall.(5) There is a kind of response relationship between the groundwater depth in research areaand the vegetation ecosystem. In the grassland of West Liao River Plain, the vegetation coverage will be affected significantly when the average depth of groundwater is less than4m; the condition is suitable for the vegetation growth when the vegetation depth is between0.5 and 2.7; the depth of the groundwater will not be the most important affecting factor forthe vegetation of grassland when the depth of groundwater is more than 4m.The innovative points of the paper are as follows.(1) The further research on the relationship between vegetation coverage rate and thegroundwater depth will be compeleted by utilizing GIS spatial analysis technology.(2) The vegetation evolutionary tendency of research region will be predicted and analyzedfor the first time by using the combination method of mathematical statistics and GIS spatialanalysis techniques based on the analysis on relationship between dynamic groundwater andthe macroscopic change response of vegetation in West Liao River Plain.更多还原