【作者】 贾丹；

【导师】 冯仲科； 马小计；

【作者基本信息】 北京林业大学 ， 林业装备工程， 2009， 博士

【摘要】 随着社会的进步,生态环境问题越来越受到世界的普遍关注。北京地区的生态环境比较脆弱,尤其是风沙问题一直困扰着北京的发展。近年来为保障北京的生态安全和改善环境质量,国家和政府投入了巨大的财力和人力,把风沙防治作为生态环境建设的重要组成部分,开展了一系列的防沙治沙工程,使其生态环境得到一定程度的改善。但从总体上分析,北京市的生态环境状况还比较脆弱,生态质量不高,其防沙治沙任务仍然十分艰巨。鉴于此背景,本文选取北京市重点风沙危害区—延庆风沙区为典型区域,以1962～2005年地面气象记录和三期TM影像(1989年、1996年和2005年)为主要数据源,运用3S技术,结合野外观测、景观生态学、生态风险理论和自然灾害理论,进行景观生态风险研究,客观分析和评价了区域景观结构生态风险和风沙扩散风险水平,并对风沙扩散灾害进行了模拟。在此基础上,应用景观生态学原理,从理论和方法上探讨区域景观格局优化配置问题,以期为当前区域生态风险水平下减少风沙扩散灾害找出切实可行的格局优化模型。本文包括如下几个部分:首先,根据研究区特点,收集并处理图形、图像和文字数据,在GIS中构建研究区基础数据库;其次,结合景观生态风险理论,以1996和2005两期遥感影像为数据源,以人为活动为风险源,通过Frag软件计算得到的景观格局指数去构建景观生态风险指数,并划分风险小区,进行风险指数计算,最后通过克里格插值,把风险结果反映到空间上。结果表明:2005年区域内的生态风险相比1996年整体上有了很大的降低,生态环境得到了很好的改善,但是区域内的高生态风险区仍然存在。第三,根据自然灾害风险理论方法,本研究从致灾因子和孕灾环境两个方面出发,在深入分析了降雨、风等气象致灾因子的基础上,选取植被覆盖度、土地利用类型、植被干旱指数、土壤类型四个指标指标,建立风沙扩散的危险性评价体系,在GIS环境中实现对研究区风沙扩散风险评价,确立风沙扩散危险等级;在下垫面风沙扩散危险性评价的基础上,结合致灾风力强度,对研究区进行风沙扩散风险评价,确定研究区风沙扩散风险等级的空间分布区域,评价结果表明:风险等级从高度、较高、中等、较低到低度,所对应的区域面积分别占研究区总面积的7.57%、29.38%、14.28%、26.23%和22.54%;第四,利用地理信息系统技术,根据景观生态流运行受空间距离、障碍物等因素影响的原理,构建累积耗费距离模型,并结合风险扩散风险评价,在GIS系统中实现风沙扩散致灾情景的模拟。第五,从景观功能角度出发,通过景观结构生态风险评价结果和风沙扩散生态风险评价结果的结合来分析景观生态功能空间强度,通过累积耗费模型构建生态廊道和生态结点,从而对研究区进行格局优化。现在国内外对风沙灾害危险性评价及治理对策的研究比较多,但从风险角度分析风沙扩散,并把景观结构生态风险和风沙扩散生态风险评价与景观生态功能空间特性相结合寻找防治风沙扩散的模式的研究较为欠缺,本文致力于这方面的研究与探讨。选题以景观生态风险理论、景观生态学理论为指导,运用3S技术和最小耗费模型等新方法,综合多个多学科知识,在理论基础上做防沙治沙方面的探索,为风沙防治、灾害预防提供科学依据,有一定的理论创新意义。更多还原

【Abstract】 With the progress of the society,more and more attention is paid to sandstorm and the resulting ecological problems in the whole world.Beijing also suffers from the natural disaster.In recent years, sandstorm diffusion happened frequently and has caused serious problems.In order to improve the environmental quality and protect the ecological safety,governments have taken some measures,But from the overall analysis,we can see that Beijing’s ecological environment is more frangible,and ecological quality is more lower.Corresponding,the task of preventing and controlling desertification is severely difficult and important.A case study was carried out in Yanqing Sandstorm District,which is located in the northwest suburb of Beijing.In this artical,based on 3S techniques,we took 30-m resolution Landsat Thematic Mapper(TM) images(in 1989,in 1996,in2005) of the Beijing region and the climate data from 1962 to 2005 as the date foundation,and used integrated approaches of field investigation,landscape ecology theory,principle of landscape ecological risk and natural disaster theory.We objectively analyzed and assessed the risk of landscape structure and wind erosion in research region,and simulate the sandstorm diffusion.Based on that,according to methods of landscape ecology and ecological risk theory,this study discusses the landscape optimization pattern theoretically and technically for controlling desertification and reducing sandstorm diffusion disaster in the research areas.This paper includes the following several parts:Firstly,base on the conditions in Yanqing,we through collect and deal with many correlative data to build fundamental geographic database in GIS environment;secondly,According to risk theory of Landscape Ecology and natural disasters theory,we used landscape structure index to Construct Landscape ecological risk index.By risk cell division,we calculated the risk index.At last,through kriging prediction,we get the map of Landscape ecological risk.The results indicate:As a whole,in the research distract,in 2005,the ecological risk decreased obviously more than what in 1996,but but high ecological risk distract still exist.Thirdly,according to risk theory of Natural Disasters,we analyze the disaster-pregnant environment and natural disaster-causing factors of study field,and select four indicators(land use,vegetation cover,TDVI and soil type) to assess the sandstorm hazard of underlying surfaces in the research field.According to the study the five classes of blown sand disaster degree were defined,the results indicate that from very low risk level to very high risk level,and the proportion of corresponding land areas are 7.57%、29.38%、14.28%、26.23%和22.54%respectively;on the base of sandstorm disaster hazard assessment based on GIS environment,by combining with the wind forces factors create the spatial pattern of sandstorm diffusion risk.It synthetically explains the spatial distribution character of the risk level;fourthly,in a landscape the movements of flow,energy and material are common related to some factors such as distance,time,impedance,etc.according to the principle we built the accumulative cost distance model,and combines with above sandstorm,diffusion risk assessment achievement,we simulate the sandstorm diffusion use GIS technology;at last,based on the landscape function theory,combines with landscape ecological risk assessment achievement and sandstorm.Diffusion risk assessment achievement to analyzes the spatial difference of the ecological function in Yanqing and through accumulative cost distance model to built the ecological corridors and ecological nodes for the landscape pattern optimization in wind-eroded regions.Now,at home and abroad there are many researches on sandstorm mechanism of blown-sand activities and the hazard assessment,while from the viewpoint of risk the sandstorm diffusion research combined the results of landscape structure ecological risk assessment and risk assessment sandstorm diffusion with ecological spatial character of landscape are quite rare for combating and controlling desertification.The article ’s aim is to explore and study in this field.This paper tries to revise the common theory for sandstorm diffusion and natural disaster prevention guided by the landscape ecology and ecological risk theory,based on accumulative cost distance model and 3S techniques.更多还原