【作者】 那音太；

【导师】 乌兰图雅；

【作者基本信息】 内蒙古师范大学 ， 自然地理， 2008， 硕士

【摘要】 荒漠化评价技术研究是荒漠化研究领域的核心内容之一,对荒漠化过程进行适时的评价和监测,掌握荒漠化发生的动态和机理,及时准确地评价荒漠化发生的程度,是建立荒漠化预警系统的基础,同时也可为国家及区域荒漠化防治工程合理布局及决策提供科学依据。荒漠化遥感监测的关键技术是从遥感图像中提取荒漠化信息。本研究以科尔沁左翼后旗2000年和2007年TM、ETM+原始影像为主要信息源,结合野外考察、地面定位取样,以及在前人研究的基础上,探索草原荒漠化遥感信息的提取方法,进而对21世纪初科尔沁沙地荒漠化现状及其动态趋势进行定量评价,并指出荒漠化治理过程当中存在的问题以及改善对策。通过波段组合计算植被指数,同时对NDVI、SMAVI算出来的植被覆盖度结果进行比较。比较表明以TM、ETM+为数据源的基于NDVI计算出来的植被覆盖度比基于SMAVI算出来的更接近于科左后旗实地考察情况,更具有科学性。在基于植被覆盖度的科尔沁左翼后旗荒漠化等级评价的基础上,结合土壤亮度指数和土壤湿度指数,三者共同作为评价指标,利用遥感决策树分类法把科尔沁左翼后旗的荒漠化分为三种类型。监测结果显示2007年科左后旗荒漠化土地总面积为5660.14km~2,占总土地面积的49.02%。其中,重度荒漠化土地面积为3276.79km~2,占荒漠化土地总面积的57.89%;轻度和中度面积分别为1569.83km~2和813.5181km~2,分别占荒漠化土地面积的27.73%和14.37%;未荒漠化土地面积为5822.02km~2,占总土地面积的50.42%。决策树分类结果显示2007年荒漠化类型中风蚀荒漠化面积为5336.87km~2,占当年荒漠化土地总面积的94.29%;盐碱荒漠化和水蚀荒漠化土地面积分别为276.42km~2和46.85km~2,分别占荒漠化土地面积的4.88%和0.83%。从21世纪动态变化来看,近8年间科左后旗荒漠化土地总面积减少了567.03km~2,年均减少70.87 km~2,荒漠化程度基本稳定并有所减弱。荒漠化土地面积在总土地面积中的比例从2000年的53.93%下降到2007年的49.02%。轻度、中度荒漠化土地面积有所减少,其中轻度荒漠化土地面积减少了2188.22km~2,中度荒漠化土地面积减少了424.93km~2;重度荒漠化和未荒漠化土地面积有所增加,其中重度荒漠化土地面积增加了2046.13km~2,未荒漠化土地面积增加了587.25km~2。从荒漠化类型来看,风蚀荒漠化土地面积变化最大,从2000年的5852.76km~2减少到2007年的5336.87km~2,比2000年减少了8.81%。水蚀荒漠化由2000年的12.23 km~2增加到2007年的46.85 km~2,盐碱荒漠化从2000年的362.17km~2减少到2007年的276.42km~2 ,减少了23.68%。从土地荒漠化变化空间分布特征来看,荒漠化稳定地区主要分布在该旗西部和中部地区,逆转的地区主要在东部和南部地区,荒漠化发展地区主要分布在该旗北部和西北地区。21世纪初科尔沁沙地荒漠化变化驱动因子以地表组成物质、气候条件等自然因子为基础,人为因子起主导作用。人们对科尔沁沙地采取了多种治理措施,这些措施在气温变暖、降水量减少和蒸发量增加等加剧荒漠化的不利条件下,仍使科尔沁沙地荒漠化基本稳定或甚至有所减弱的方向发展。更多还原

【Abstract】 Land desertification evaluation technology study is one of the key contents of desertification study area. To conduct timely evaluation and monitoring on the desertification process and master the dynamic and mechanism of desertification occurrence and accurately evaluate the degree of desertification on time is the basis of constructing desertification forecasting system. At the same time it can provide scientific evidence for national and regional reasonable layout and decision of desertification prevention project.The key technique of desertification remote sensing monitoring is extracting desertification information from remote sensing images.In combination with field investigation,take sample of ground positioning, and search the desertification information extraction method on the basis of research of preceding. And to quantitatively evaluate 21 century KEERQIN desert desertification condition and it’s dynamic trend and point out the existing problem and it’s improvement policy in the process of desertification treatment.This study’s main information sources are the original image of KEERQIN ZUOYIHOUQI TM、ETM+ image in 2000 and 2007.By means of band combination, calculate the vegetation index and at the same time compared the vegetation coverage result on the basis of NDVI、SMAVI. After comparison it is found out that vegetation coverage based on the SMAVI is more practical and scientific for the actual investigation condition of KEERQIN ZUOYIHOUQI compared with the vegetation coverage based on the NDVI. On the basis of evaluation of desertification grades to the vegetation coverage of KEERQIN ZUOYIHOUQI, and in combination with soil brightness index and soil wetness index for the three evaluation index, and make use of remote sensing decision tree classification method to classify the desertification of KEERQIN ZUOYIHOUQI to three kinds of desertification.Monitoring result shows that total desertification area of KEERQIN ZUOYIHOUQI in 2007 is 5660.14 km~2and accounts for 49.02% of the total land area. Among them heavy desertification land area is 3276.79km~2 and accounts for 49.02% of total desertification land area; Light and medium desertification land area is 1569.83km~2and 813.5181km~2 respectively and accounts for 27.73% and 14.37% of the total desertification area. Not desertification land area is 5822.02km~2 and accounts for the 50.42% of the total land area. Result of decision tree classification shows that area of wind erosion desertification is 5336.87 in desertification types in 2007, and accounts for 94.29% of land desertification area.Salty desertification and water erosion desertification land area is 276.42km~2 and 46.85km respectively and accounts for 4.88% and 0.83% Of the desertification land area.From the 21 century’s beginning dynamic changes, in recent8 years KEERQIN ZUOYIHOUQI total land desertification area reduced 567.03km~2,reduced 70.87 km~2 annually从degree of desertification stabilized basically and reduced. Desertification land area reduced to 49.02% in 2007 from 53.93% in 2000 in total land area. Light and medium desertification land area reduced, land area of light desertification land area reduced 2188.22km~2 and medium desertification land area reduced 424.93km~2. Heavy desertification and not desertification land area increased and heavy desertification land area increased 2046.13km~2 and not desertification land area increased 587.25km~2。From the point of desertification types, change of wind erosion desertification land area is the biggest. It reduced from 5852.76km~2 in 2000 to 5336.87km~2 in 2007 by 8.81%。Water erosion desertification increased from 12.23 km~2 in 2000 to 46.85 km~2 in 2007. salty desertification reduced from 362.17km~2 in 2000 to 362.17km~2 in 2007 by 23.68% From the characteristic of land desertification spatial distribution changes, the desertification stable area mainly distributes in the western and middle part of this banner. In converse area mainly distributes in the eastern and southern area. Desertification developing area mainly distributes in the north and northwestern area.The driving force basic factor of 21 century beginning’s land desertification changes is the natural factor such as composition material of land surface and climate condition. Human factor had dominant functions. People took many kinds of treatment measures. These measures at the desertification severe disadvantageous condition such as the climate warming and reduction of rainfall and increasing of evaporation still make the KEERQIN sand area stable basically and developing towards the desertification reduction.更多还原