Sandy Desertification Status and its Driving Mechanism in North Tibet Plateau

As the main body of Qinghai-Tibetan Plateau, North Tibet Plateau is one of three major sandy desertification regions in China and also a representative sandy desertification zone of Qinghai-Tibet Plateau. Accordingly, it is an important region for the study of recent sandy desertification processes and formation mechanism. From such aspects as desertified land types, areas and distributions etc., this paper analyses in detail the sandy desertification status on North Tibet Plateau, and qualitatively and quantitatively deals with the main factors that affect recent sandy desertification processes and the driving mechanism. Research results show that North Tibet Plateau is an important sandy desertificafion region in China characterized with large desertified land areas, diversified types, high severity, extensive distributions and serious damages. Sandy desertification occurrence and development resulted from combined effects of natural factors, anthropogenic factors, natural processes and man-made processes, of which climatic change is the main driving force.     

青海湖区土地荒漠化遥感地学分析

青海湖是我国最大的内陆咸水湖,是世界著名的湿地,但随着周围地区荒沙漠化环境的恶化,其土地荒漠化也不断加剧。本文对青海湖地区土地荒漠化的自然特征和社会经济特征进行了分析,明确了荒漠化的环境背景。在此基础上,结合青海湖地区荒漠化土地普查与监察工作的范围和内容,采用ASTER卫星影像图对湖区周围地区进行解译,并利用解译数据对荒漠化土地进行等级划分,分析土地荒漠化的空间分布格局,对荒漠化作出综合评价。     

雅鲁藏布江中部流域土地沙化遥感识别

雅鲁藏布江中部流域长期遭受土地沙化侵蚀,采取有效手段进行沙化土地信息快速识别,跟踪土地沙化现状和动态发展,是土地沙化防治的基本前提。遥感数据因其快速、大范围、高精度监测等特点已被广泛应用于土地沙化监测。为降低该区域沙化土地破碎化分布特征以及广泛分布的稀疏植被地表对沙化土地遥感识别带来的不确定性,本文利用Google Earth Engine平台获取2019年秋季雅鲁藏布江中部流域Landsat无云遥感影像,基于面向对象的分类思想,充分提取沙化土地的光谱、几何和地形特征,根据不同的分类器构建4种分类方案,包括单一分类器（支持向量机、决策树、最近邻）分类以及组合分类法分类,提取雅江中游河谷地区沙化土地信息并验证不同方案的提取精度。结果表明：① 利用面向对象组合分类模型提取的沙化土地信息效果最佳,总体精度高达91.38 %,Kappa系数为0.82;② 相较于采用单一分类器（支持向量机、最近邻和决策树分类）的面向对象分类方法,组合分类模型能更有效地识别破碎化的小面积沙化土地,降低沙化土地与稀疏植被地表的混淆情况,提高分类可靠性;③ 基于面向对象组合分类模型反演得到雅鲁藏布江中部流域2019年沙化土地分布信息,土地沙化面积达299.61 km²,总体上呈现沿河谷的带状不连续分布,且集中分布于河流北岸以及靠近河道的阳坡、低海拔地区。本研究可为土地沙化遥感监测提供新思路,其应用可服务于雅鲁藏布江中部流域土地沙化预防和治理工作。     

THE CAUSES AND DEVELOPMENTAL TREND OF DESERTIFICATION IN THE MIDDLE REACHES OF THE YARLUNG ZANGBO RIVER AND ITS TWO TRIBUTARIES IN XIZANG

ＴＨＥＣＡＵＳＥＳＡＮＤＤＥＶＥＬＯＰＭＥＮＴＡＬＴＲＥＮＤＯＦＤＥＳＥＲＴＩＦＩＣＡＴＩＯＮＩＮＴＨＥＭＩＤＤＬＥＲＥＡＣＨＥＳＯＦＴＨＥＹＡＲＬＵＮＧＺＡＮＧＢＯＲＩＶＥＲＡＮＤＩＴＳＴＷＯＴＲＩＢＵＴＡＲＩＥＳＩＮＸＩＺＡＮＧＤｏｎｇＧｕａｎｇ...     

A STUDY ON DESERTIFICATION OF WEST JIJLIN PROVINCE BASED ON REMOTE SENSING AND GIS TECHNIQUES

“West Jilin Porovince” in ths paper means Zhenlai,Baicheng,Taonan,Da‘an,Tongyu,Fuyu,Songyuan,Qian‘an ,Chandling,also includes Gongzhuling,Shuangliao,Lishu,Siping and Nong′an which have been suf-fered from desertification.In west Jilin Province there are three sand zones passing through,they are Xiang(Xianghai)-Wu(Wlan Tug)sand zone,Hai-Fent sand zone,and Tao′er River right band sand zone.The desertification area of west Jilin Province is 819 100ha,making up 12.5% of the total land area.Among desertification types,in Jilin Province light desertification is the major,then is medium dersertification,hevey desertification is the least.According to the compare-son of the interpretation results of the Landsat images of the 1980s and 1990s by remote sensing and GIS techniques,it can be seen that the diesertification area in west Jilin Province basically didn′t change on the whole,only increased 6130ha,making up 0.8% of the desertification area,change scale is less than 1%.Evidently,desertification is con-trolled mostly,but some areas are continuing deterioration.The desertification process of China can be divided into three types according to origin nature,they are sandy steppe desertification,fixed sand area(sand land) activation and dunes transfer invasion.Reasons of desertification of West Jilin Province are analyzed,they include natural factors(such as material source factors,chimate factors) and artificial factors(such as destroying grass to reclaim,steppe decreasing greatly,illegally feeling shelter forest stands,constructing reservoir to influence eco-environment etc.).Some sugges-tions are put forward as follows:establishing the social project for ecological reconstruction of degenerated land;intensify-ing planning and management of land use,reverting farmland into forestland or pasture in a planned way.The key desertifica-tion control is to depend mainly on policy and management,then control techniques.     

Desertification hazard and farming-grazing sustainable development in Lingwu-Yanchi region of Ningxia

１ＰＲＯＣＥＳＳＯＦＤＥＳＥＲＴＩＦＩＣＡＴＩＯＮＡＮＤＩＮＦＬＵＥＮＣＥＯＦＰＨＹＳＩＣＡＬＥＮＶＩＲＯＮＭＥＮＴＡＮＤＨＵＭＡＮＡＣＴＩＶＩＴＹＩＮＬＩＮＧＷＵＹＡＮＣＨＩＲＥＧＩＯＮＴｈｅｄｅｓｅｒｔｉｆｉｃａｔｉｏｎｈａｚａｒｄｉｎＬｉ...     

DYNAMICS OF SANDY DESERTIFICATION AND ITS DRIVING FORCES IN WESTERN JILIN PROVINCE

By establishing the interpreting elements, and applying supervised classification, the sandy desertification was interpreted and the desertified land areas of the counties in the western Jilin Province in 1986 and in 2000 were obtained. Taking Tongyu and Qian‘an as examples, the natural driving forces and man-made driving forces were analyzed. The paper comes the conclusions that the material sources and the warming and dry climate are the internal causes of potential land descrtification: the irrational human activities, such as destroying forest and reclaiming the grassland, are the external causes of potential land desertification; while more rational human activities, such as planting trees and restoring grassland can reverse the land desertification. Furthermore, the countermeasures and suggestions for the development of agriculture and animal husbandry in the western Jilin Province are put forward.     

中国荒漠化分区与时空演变

荒漠化被列入威胁人类生存的十大环境与发展问题之一,中国作为世界上荒漠化严重的国家,荒漠化形势十分严峻。本文通过遥感手段,以中国陆域国土范围（除台湾、香港和澳门）的31个省、市、自治区为研究区域,对1975年、2000年与2017年研究区数据进行沙化、盐渍化、水蚀荒漠化专题因子时空演变的综合研究,根据地域分异、发生学及多级序列等原则将将中国划分为8个荒漠-荒漠化区,42个荒漠-荒漠化亚区和36个荒漠-荒漠化小区。以不同时期荒漠化土地类型图为依据,采用荒漠化面积变化量与荒漠化重心迁移轨迹指标进行荒漠化演化分析。为具体说明不同区域荒漠化程度,本研究根据一定时期内荒漠化土地面积增加或减少的百分比将荒漠化演化分为7种类型,通过分析得到不同荒漠化区域的时空演化及不重心迁移,据此提出中国荒漠化的重点治理目标区及防治建议。研究结果表明：① 中国荒漠、荒漠化土地种类较多,重度荒漠化面积25.18×10⁴ km²,占荒漠化总面积的19.59%;② 1975-2017年,中国荒漠化发生明显逆转,与1975-2000年相比,2000-2017年全国的荒漠化强度显著下降,原因是荒漠化加重区面积减少以及荒漠化减弱区面积增加;③ 1975-2000年与2000-2017年,各区内荒漠化重心点坐标迁移具有同向性。本研究在分析荒漠化土地分布、形成和演变机制的基础上,进行了荒漠化分区。通过对不同荒漠化地区的面积百分比变化的比较,得到了不同时期荒漠化的时空演化模式,并分析了荒漠化演化的特点和差异。     

Rocky Desertification Risk Zone Delineation in Karst Plateau Area： A Case Study in Puding County, Guizhou Province

Karst rocky desertification is a geo-ecological problem in Southwest China. The rocky desertification risk zone delineation could be used as a guide for the regional and hierarchical rocky desertification management and prevention. We chose the middle and lower reaches of the Houzhai underground basin on the karst plateau in Puding County, Guizhou Province, China as the study area and selected land use type, elevation, slope, aspect, lithology and settlement buffer as the main driving factors of the rocky desertification. The potential risk of rocky desertification was quantified with the factor-weights union method and statistical analysis method. Five grades of rocky desertification risk were delineated based on Geographic Information System. The extremely low, low, moderate, high and extremely high rocky desertification risk zones accounted for 5.01%, 44.17%, 33.92%, 15.59% and 1.30%, respectively. As a whole, the rocky desertification risk level was moderate because the area of low and moderate rocky desertification risk zones occupied 78.09% of the study area. However, more than half of the area (about 50.81%) was predicted to have moderate rocky desertification risk and above, indicating that the study area was subject to rocky desertification. Rocky desertification risk was higher in the southeast and lower in the northwest of the study area. Distinct differences in the distribution of rocky desertification risk zones corresponding to different factors have been found.     

基于无人机航摄影像的喀斯特地区裸岩信息提取及景观格局分析

喀斯特地区不同石漠化等级的结构和格局是实现区域石漠化治理的重要基础信息,受技术手段的限制,目前这方面的研究进展仍非常缓慢。随着无人机技术的快速发展,高精度的地表信息获取越来越方便、且成本较低。本研究利用无人机影像,对比了基于像元的非监督和监督分类方法以及面向对象的分类方法在裸岩信息提取中的表现,发现面向对象分类结果具有更高精度。基于获得的裸岩分布信息的研究结果表明：① 岩石平均斑块面积与裸岩率呈负相关的关系,岩石斑块个数与裸岩率呈正相关关系;② 通过对比不同裸岩率（11%、20%、29%和48%）基质的景观斑块指数、景观形状指数和景观破碎度指数对不同裸岩率的景观分布的影响,从而表明了在不同的石漠化地区随着裸岩率的增加,岩石形状指数与岩石破碎度指数均逐渐增加,进而表明石漠化程度越严重;③ 裸岩率不同的地区表现不同的分布形态和斑块特征,裸岩率越高,岩石越破碎,斑块分布较为分散。小尺度斑块景观格局与区域的生态过程有着重要关系,开展小尺度景观格局的研究会深化区域尺度石漠化发展过程的理解。石漠化地区的小尺度斑块景观格局变化影响区域的生态过程,对以后的石漠化过程以及未来石漠化演变的发展有重要的启示作用。     

THE DYNAMIC MONITORING OF HORQIN SAND LAND USING REMOTE SENSING

Hurqin Sand Land is regarded as the typical region for studying the problem of desertification.The integra-tion of 3S(GIS,GPS and RS)techniques offer a most helpful method to study and monitor the dynamics of desertification.Based on the data derived from 3 periodsˊmultitemporal Landsat TM imagery of the 1990s,the regional land use and dynamo-ics of desertification in Horqin Sand Land were studied.The main results revealed that :1)as long as the general change tendency was concerned,the desertification of Horqin Sand Land would continue to spread;2)there was a gradual de-crease in the area of both moving sand dunes and semi-stabilized ones,which meant that fruitful progress had been made to control the desertification during the 1990s;3)as a result of unreasonable cultivation,the total area of stabilized sand dunes and grassland in the middle and western region decreased obviously.It suggested that the increasing damage caused by human was leading to the hazard of further desertification.So in the future,it is necessary to take more effect-tive measures to control the spread of desertification and restore the degraded ecosystems for the purpose of optimizing the global eco-environment in Horqin Sand Land.     

Rocky land desertification and its driving forces in the karst areas of rural Guangxi,Southwest China

With a subtropical climate, Guangxi Zhuang Autonomous Region has a typical karst landscape. Rocky desertification has become a serious environmental issue due to its high vulnerability caused by the joint effect of natural settings and human activities, because of which its eco- environment has been deteriorated in recent years, and farmland has been disappearing sharply at the same time. This, in turn, has exacerbated the poverty level in the rural areas of the region. In this study, we monitored the spatial distribution of rocky land desertification and its temporal evolution using Landsat TM/ETM images of 1985, 1995, 2000 and 2005. We also analyzed the driving forces of the desertification and its expansion. Through constructing regression models by using all the relevant variables and considering the lagged effects as well as fixed effects, we quantified the exact role of different factors causing rocky land desertification in the study area with some new findings. The new findings in this study are greatly helpful for preserving, restoring and reconstructing the degraded mountain environment in Guangxi and other karst areas in Southwest China, and also for alleviating poverty in the rural areas in the future.     

遥感石漠化信息的提取

石漠化信息提取是多种信息综合分析、反馈的过程。通过分析当前石漠化分级体系,对比喀斯特地区与石漠化范围、土地利用与石漠化关系,并结合当前石漠化信息提取关键技术研究认为:目前的石漠化分级体系在划分级别、分级指标、分级区域等方面存在巨大差异,将尺度划分引入石漠化等级体系是统一石漠化等级划分差异的有力途径;充分利用基于内容的特征识别算法进行喀斯区的圈定可以有效提高石漠化信息提取精度;利用已有的土地利用矢量数据,通过合理转换进行石漠化信息提取是重要研究思路;传统的建立石漠化解译标志、改进植被指数模型以及建立波谱关系模型等石漠化信息提取方法无法很好融合石漠化综合指征,提出基于遥感的石漠化综合指标度进行石漠化信息的提取方法。     

HISTORICAL DESERTIFICATION PROCESS IN HEXI CORRIDOR, CHINA

1IN TR O D U CTIO NH istoricdaelsertificatiisonnotonlythekeyissueon theinteractiobnetweennatureandhuman proces,sbutalsothemost challenginigssueinthecomplex reltaionshipbetweenhuman andland.Previousl,ymostChinesesci-entistisnthisfieldcarrieoduttheiresearch…     

Impact of water environmental characteristics in Dry-Hot valley of Jinsha river on soil desertification

Ｗｉｔｈｔｈｅｓｏｃｉａｌｄｅｖｅｌｏｐｍｅｎｔ,ｈｕｍａｎｂｅｉｎｇｓｈａｄｔｏｐａｙｍｕｃｈａｔｅｎｔｉｏｎｔｏｔｈｅｃｒｉｓｉｓｏｆｅｎｖｉｒｏｎｍｅｎｔａｓｔｏｔｈｅｅｃｏｎｏｍｉｃｃｒｉｓｉｓ．Ｗａｔｅｒｄｅｆｉｃｉｅｎｃｙａｎｄｄｅｓｅｒ...     

干旱半干旱地区土地沙漠化信息系统的设计与应用

“数字地球”战略的提出得到各界人士的广泛关注,并从各自专业角度献计献策。但“数字地球”战略的实施必须以区域或专题为切入点。本文从我国干旱半干旱地区沙漠化比较严峻及西部大开发以生态环境建设为目标的背景出发,结合研究区的自然、人文特征,设计干旱半干旱地区沙漠化信息系统的总体结构、功能、模型,系统包括数据库管理子系统、土地沙漠化信息查询子系统、模型库管理子系统等。系统设计的同时选择典型示范区进行了实践。结果表明,系统在其数据项相关性方面已满足本专题GIS系统的功能和模型的要求,本系统可为生态环境恶化、土地沙漠化预测与评估以及决策部门及时采取防治措施和对策。提供迅速、动态的信息和技术支撑。     

塔里木河流域综合治理生态要素变化的遥感分析

采用多种类、多时相遥感数据对塔里木河流域综合治理后的耕地变化和干流绿色走廊带的植被、沙质荒漠化和盐碱质荒漠化等主要生态要素进行了动态监测,结果表明:(1)1999-2008年间,流域耕地面积逐步扩大,从167.17万hm2增长到207.51万hm2。其中,塔里木河干流区耕地面积增加最快,叶尔羌河、开都河-孔雀河与和田河三流域稳步增加,而阿克苏河流域耕地面积先增加,后减少。除阿克苏河流域外,塔里木河流域等其他三流域和塔里木河干流,在2004-2008年间的面积增长速度明显大于1999-2002年和2002-2004年两个时段。(2)2002-2004年间,塔里木河干流绿色走廊带生态环境明显改善,主要表现为植被覆盖度的提高、沙质荒漠化土地面积的减小和强度减弱、盐碱质荒漠化土地的强度减弱等。耕地面积的大幅度增加引起的灌溉用水量的增大,对长期采用输水实现塔里木河的生态功能恢复具有长期性制约作用。     

Human Driving Forces:Analysis of Rocky Desertification in Karst Region in Guanling County,Guizhou Province

Karst rocky desertification is one of the major ecological and environmental problems that threaten the sustainable development of southwestern China. It is caused by irrational and intensive land-use patterns in karst geo-ecological environment. Therefore, it is vital to identify how human forces work on this degraded environment. Based on the soil erosion information in 2000 and remote sensing images of Guanling County collected in 2000 and 2007, four grades of karst rocky desertification data in 14 villa...     

中国三北地区荒漠化与可持续发展

介绍了三北地区荒漠化的基本状况与特点．探讨和分析了荒漠化的发生、发展对可持续发展的主要危害以及荒漠化与可持续发展的关系等，认为三北地区对中国的社会经济发展和生态保护有着重要的作用，荒漠化的发展将限制可持续发展战略的实施．必须积极开展三北地区荒漠化防治工作。