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1.
水蚀风蚀过程中土壤可蚀性研究述评   总被引:4,自引:1,他引:3  
1 IntroductionSoil erosion is the process of detachm ent and transport of soil particles caused by w ater andw ind (M organ,1995).Soilerosion by w ater and w ind leads to decline in soilfertility,brings ona series of negative im pacts of land degradation …  相似文献   

2.
The varicolored hills in the northern foothills of the Qilian Mountains of northern China, in the Hexi Corridor of Gansu Province's Sunan Yugur Autonomous County, have given this region a unique geomor...  相似文献   

3.
The Qinling Mountains, located at the junction of warm temperate and subtropical zones, serve as the boundary between north and south China. Exploring the sensitivity of the response of vegetation there to hydrothermal dynamics elucidates the dynamics and mechanisms of the main vegetation types in the context of changes in temperature and moisture. Importance should be attached to changes in vegetation in different climate zones. To reveal the sensitivity and areal differentiation of vegetation responses to hydrothermal dynamics, the spatio-temporal variation characteristics of the normalized vegetation index(NDVI) and the standardized precipitation evapotranspiration index(SPEI) on the northern and southern slopes of the Qinling Mountains from 2000 to 2018 are explored using the meteorological data of 32 meteorological stations and the MODIS NDVI datasets. The results show that: 1) The overall vegetation coverage of the Qinling Mountains improved significantly from 2000 to 2018. The NDVI rise rate and area ratio on the southern slope were higher than those on the northern slope, and the vegetation on the southern slope improved more than that on the northern slope. The Qinling Mountains showed an insignificant humidification trend. The humidification rate and humidification area of the northern slope were greater than those on the southern slope. 2) Vegetation on the northern slope of the Qinling Mountains was more sensitive to hydrothermal dynamics than that on the southern slope. Vegetation was most sensitive to hydrothermal dynamics from March to June on the northern slope, and from March to May(spring) on the southern slope. The vegetation on the northern and southern slopes was mainly affected by hydrothermal dynamics on a scale of 3–7 months, responding weakly to hydrothermal dynamics on a scale of 11–12 months. 3) Some 90.34% of NDVI and SPEI was positively correlated in the Qinling Mountains. Spring humidification in most parts of the study area promoted the growth of vegetation all the year round. The sensitivity of vegetation responses to hydrothermal dynamics with increasing altitude increased first and then decreased. Elevations of 800 to 1200 m were the most sensitive range for vegetation response to hydrothermal dynamics. The sensitivity of the vegetation response at elevations of 1200–3000 m decreased with increasing altitude. As regards to vegetation type, grass was most sensitive to hydrothermal dynamics on both the northern and southern slopes of the Qinling Mountains; but most other vegetation types on the northern slope were more sensitive to hydrothermal dynamics than those on the southern slope.  相似文献   

4.
陕北地区退耕还林还草工程土壤保护效应的时空特征   总被引:1,自引:1,他引:0  
This paper looks at the Green for Grain Project in northern Shaanxi Province.Based on remote sensing monitoring data,this study analyzes the locations of arable land in northern Shaanxi in the years 2000,2010 and 2013 as well as spatio-temporal changes over that period,and then incorporates data on the distribution of terraced fields to improve the input parameters of a RUSLE model and simulate and generate raster data on soil erosion for northern Shaanxi at different stages with a accuracy verification.Finally,combined with the dataset of farmland change,compared and analyzed the characteristics of soil erosion change in the converted farmland to forest(grassland)and the unconverted farmland in northern Shaanxi,so as to determine the project’s impact on soil erosion over time across the region.The results show that between 2000 and 2010,the soil erosion modulus of repurposed farmland in northern Shaanxi decreased 22.7 t/ha,equivalent to 47.08%of the soil erosion modulus of repurposed farmland in 2000.In the same period,the soil erosion modulus of non-repurposed farmland fell 10.99 t/ha,equivalent to 28.6%of the soil erosion modulus of non-repurposed farmland in 2000.The soil erosion modulus for all types of land in northern Shaanxi decreased by an average of 14.51 t/ha between 2000 and 2010,equivalent to 41.87%of the soil erosion modulus for the entire region in 2000.This suggests that the Green for Grain Project effectively reduced the soil erosion modulus,thus helping to protect the soil.In particular,arable land that was turned into forest and grassland reduced erosion most noticeably and contributed most to soil conservation.Nevertheless,in the period 2010 to 2013,which was a period of consolidation of the Green for Grain Project,the soil erosion modulus and change in volume of soil erosion in northern Shaanxi were significantly lower than in the previous decade.  相似文献   

5.
Soil erosion and management on the Loess Plateau   总被引:6,自引:3,他引:3  
1 Introduction The Loess Plateau situated in northern China covers the drainage basins in the middle reaches of the Yellow River. It starts from the western piedmont of Taihang Mountains in the east, reaches the eastern slope of the Wushao and Riyue mountains, connects the northern part of the Qinling Mountains in the south and borders the Great Wall in the north, covering an area of about 380,000 km2 (Figure 1). The region is overlain extensively by Quaternary loess in great thickness, …  相似文献   

6.
新疆森林资源动态分析   总被引:6,自引:0,他引:6  
1 M ethod ofsurvey and analysis1.1 Survey area and dataThe survey area am ounted to 1.647 m illion km 2,covering the w hole territory of X injiang.TheLandsat TM im age data obtained from rem ote sensing in w hole X injiang during the periods1995-1996 and …  相似文献   

7.
This study examined the spatial distribution of the continent coastline in northern China using remote sensing and GIS techniques, and calculated the fractal dimension of the coastline by box-counting method, with a time span from 2000 to 2012. Moreover, we ana- lyzed the characteristics of spatial-temporal changes in the coastline's length and fractal di- mension, the relationship between the length change and fractal dimension change, and the driving forces of coastline changes in northern China. During the research period, the coast- line of the study area increased by 637.95 km, at a rate of 53.16 km per year. On the regional level, the most significant change in coastline length was observed in Tianjin and Hebei. Temporally, the northern China coastline grew faster after 2008. The most dramatic growth was found between 2010 and 2011, with an increasing rate of 2.49% per year. The fractal dimension of the coastline in northern China was increasing during the research period, and the most dramatic increase occurred in Bohai Rim. There is a strong-positive linear relation- ship between the historical coastline length and fractal dimension (the correlation coefficient was 0.9962). Through statistical analysis of a large number of local coastline changes, it can be found that the increase (or decrease) of local coastline length will, in most cases, lead to the increase (or decrease) of the whole coastline fractal dimension. Civil-coastal engineering construction was the most important factor driving the coastline change in northern China. Port construction, fisheries facilities and salt factories were the top three construction activi- ties. Compared to human activities, the influence of natural processes such as estuarine deposit and erosion were relatively small.  相似文献   

8.
Modern climate research has shown that the Asian summer monsoon water vapor transport is limited to the eastern part of the Qilian Mountains. On the Holocene millennial-scale, whether the northwest boundary of the summer monsoon varies according to climate change is a key scientific issue. Yanchi Lake is located in the northern Qilian Mountains and the middle of the Hexi Corridor, where the modern climate is less affected by the Asian summer monsoon. It is a key research area for examining the long-term variations of the Asian summer monsoon. Paleoclimatic data, including AMS ^14C dates of pollen concentrates and bulk organic carbon, lithology, grain-size, mineral composition and geochemical proxies were acquired from sediments of Yanchi Lake. The chronological results show that the lower part of the lacustrine section is formed mainly in the Late Glacial and early Holocene period, while the proxies' data indicate the lake expansion is associated with high content of mineral salts. The middle part of this section is formed during the transitional period of the early and middle Holocene. Affected by the reworking effect, the pollen concentrates AMS^14C dates from the middle part of the section are generally older than those from the lower part. Since the mid-Holocene, Yanchi Lake retreated significantly and the deposition rate dropped obvi- ously. The Yanchi Lake record is consistent with the Late Glacial and Holocene lake records in the Qinghai-Tibet Plateau and the climatic records in typical monsoon domain, which indicate the lake expansion and the strong Asian summer monsoon during the Late Glacial and early Holocene. The long-term monsoonal pattern is different from the lake evolution in Central Asia on the Holocene millennial-scale. This study proves the monsoon impacts on the northwestern margin of the summer monsoon, and also proves the fact that the northern boundary of the summer monsoon moves according to millennial-scale climate change.  相似文献   

9.
Plant growth at northern latitudes is highly responsive to the climatic changes that have occurred over recent decades. However, the sensitivity of the phasing of the seasonal cycle of terrestrial ecosystems to a changing environment remains less widely understood. We present an investigation and comparative study of large-scale changes in seasonal cy-cling of both land surface temperature and plant growth. Our results have shown trends in-dicating a marked increased towards overall plant productivity by ~3% from 1982 to 2005, reduced trends in seasonal variation at low-mid latitudes by ~2%, increased trends in sea-sonal variations at mid-high latitudes by ~7%, and an earlier phase in northern terrestrial ecosystems (~1.1 days) in parallel with changes in the phasing of surface temperatures at northern latitudes over the 24 years in this study. These shifts in annual cycles of terrestrial vegetation appear to have a distinct geographical zonality and are dependent upon latitudinal changes in climatic variables. More conspicuous changes in overall vegetation productivity and the seasonal phase of ecosystems have been observed in Eurasia compared to North America, largely because of a more rapid rise in temperature. Our results state that changing climate boosts plant growth at northern latitudes, but also alters the phase and seasonal variations of the annual cycle of terrestrial ecosystems.  相似文献   

10.
北极涛动对中国冬季气候的影响   总被引:11,自引:0,他引:11  
1IntroductionIt is noteworthy that there is significant association between the surface climate over northern continents and atmospheric circulation (Hurrell, 1995, 1996; Gong and Ho, 2002a). Thompson and Wallace (1998) pointed out that the leading empirical orthogonal function of the wintertime northern hemisphere sea level pressure field resembles the North Atlantic Oscillation but with more zonally symmetric appearance. This annular-like mode in the northern extratropical circulation, wh…  相似文献   

11.
This paper firstly selects 10 kinds of indexes to reflect eco-environment background condition and builds the multi-subject spatial database by using ground meteorological data, remote sensing data and DEM. It then discusses in detail the methods about evaluating eco-environment background condition and analyzing eco-environment change. The eco-environment background conditions of 1989 and 1999 are synthetically appraised. Finally, the paper analyzes the spatial distribution, quantitative change, the trend of change, the areas of change and the dynamic spatial pattern of eco-environment. The results are as follows: (1) The eco-environment background condition becomes worse from southeast to northwest in the farming-pastoral region of northern China. (2) The eco-environment background condition deteriorates from 1989 to 1999. (3) In the adjacent areas of Shanxi-Shaanxi-Inner Mongolia-Gansu-Ningxia, Horqin Sandy Land and its peripheries, and eastern Qinghai province, eco-environmental deterioration is very serious.  相似文献   

12.
北方13省土地利用/覆盖动态变化分析   总被引:20,自引:9,他引:11  
对北方13省1989~1999年的宏观土地利用/覆盖动态变化进行分析。结果表明:研究区草地、水体的退化以及未利用地的不断扩展增加区域生态系统的敏感性和脆弱性,生态环境压力进一步增大;土地利用/覆盖总体破碎度不断增加,土地利用向着多样化和均质化方向发展;10年间,各种土地利用/覆盖类型重心的空间位置均有所变化。水体变化最明显,其次为未利用地、耕地和城建用地;各种土地利用/覆盖类型变化表现出明显的区域差异。  相似文献   

13.
中国北方农牧交错带受自然条件和人为活动等多种因素的综合影响,生态环境退化问题比较突出,是生态环境退化研究的典型区和理想地带。以此作为研究对象,选择能反映生态环境特点的多种空间数据信息,利用数字网格模型,通过采用空间叠加的分析方法,评估北方农牧交错带的生态环境背景状况,并对其空间格局特征进行研究。结果表明:(1)北方农牧交错带生态环境背景状况从东南向西北逐渐变差;(2)在北方农牧交错带205个旗县中,绝大部分旗县的生态环境背景状况为一般;宁夏盐池县生态环境背景状况最差,河北兴隆县生态环境背景状况最好。  相似文献   

14.
1989-2003年中国北方土地覆被变化   总被引:2,自引:0,他引:2  
The 13 provinces (autonomous regions and municipalities) in northern China are located in latitude 31°-54°N and longitude 73°-136°E including Beijing, Tianjin, Hebei, Shanxi, Inner Mongolia, Jilin, Liaoning, Heilongjiang, Shaanxi, Gansu, Ningxia, Qinghai, and Xinjiang, where environments are fragile. In recent years, the eco-environmental problems such as vegetation destruction, desertification and soil erosion etc. become serious because of climate change and unreasonable human activities. In this paper, landscape pattern and its evolution in northern China from 1989 to 2003 was investigated by the combined use of RS and GIS based on the basic theory and method of landscape ecology. Land use/cover maps of the study area in 1989, 1999 and 2003 were produced by using 1 km monthly NOAA Advanced Very High Resolution Radiometer (AVHRR) and SPOTNGT Normalized Difference Vegetation Index (NDVI) dataset from national climate bureau of China which were geo-registered to Lambert azimuthal equal-area map projection and were used in the paper. Landscape evolution in the area over the study period was investigated by two methods: (a) the changes of various landscape metrics were analyzed using the landscape structure analysis program FRAGSTATS; (b) the transition matrix of landscape patch types was calculated with the help of the RS and GIS software. The results showed that from 1989 to 2003, the landscape within the study area had undertaken a complicated evolution in landscape structure and composition. The diversity index and evenness index increased during the period, which means that the landscape pattern tended to be diversified and even. The fragmentation index of grassland, forestland and water areas also increased significantly. This showed that the distribution and structure of forestland, grassland and water areas had been changed greatly during the period, especially grassland which became more and more fragmentized, and its fragmentation index increased from 19.23% to 88.72%. The transi  相似文献   

15.
LI Yuechen 《地理学报》2008,18(1):85-94
The 13 provinces (autonomous regions and municipalities) in northern China are located in latitude 31°–54°N and longitude 73°–136°E including Beijing, Tianjin, Hebei, Shanxi, Inner Mongolia, Jilin, Liaoning, Heilongjiang, Shaanxi, Gansu, Ningxia, Qinghai, and Xinjiang, where environments are fragile. In recent years, the eco-environmental problems such as vegetation destruction, desertification and soil erosion etc. become serious because of climate change and unreasonable human activities. In this paper, landscape pattern and its evolution in northern China from 1989 to 2003 was investigated by the combined use of RS and GIS based on the basic theory and method of landscape ecology. Land use/cover maps of the study area in 1989, 1999 and 2003 were produced by using 1 km monthly NOAA Ad-vanced Very High Resolution Radiometer (AVHRR) and SPOT/VGT Normalized Difference Vegetation Index (NDVI) dataset from national climate bureau of China which were geo-registered to Lambert azimuthal equal-area map projection and were used in the paper. Landscape evolution in the area over the study period was investigated by two methods: (a) the changes of various landscape metrics were analyzed using the landscape structure analysis program FRAGSTATS; (b) the transition matrix of landscape patch types was cal-culated with the help of the RS and GIS software. The results showed that from 1989 to 2003, the landscape within the study area had undertaken a complicated evolution in landscape structure and composition. The diversity index and evenness index increased during the pe-riod, which means that the landscape pattern tended to be diversified and even. The fragmentation index of grassland, forestland and water areas also increased significantly. This showed that the distribution and structure of forestland, grassland and water areas had been changed greatly during the period, especially grassland which became more and more fragmentized, and its fragmentation index increased from 19.23% to 88.72%. The transitions of the landscape types were mainly shown by the changes among forestland, grassland and farmland, and grassland changing into unable land. Over the study period, grassland and water areas had decreased remarkably, accounting for 15% and 37% from 1989 to 1999 and 24.79% and 49.25% from 1999 to 2003 respectively. The grassland and water resources play an important role in the eco-environment and economic development of the region. So, they must be protected carefully. According to the analysis, we can conclude that the eco-environment in the study area is obviously degenerated due to unreasonable human activities and climate changes and some measures should be taken to combat the environ-mental degradation.  相似文献   

16.
中国北方13省市区生态安全动态变化分析   总被引:8,自引:2,他引:6  
李月臣 《地理研究》2008,27(5):1150-1161
为了寻求我国北方生态安全条件的土地利用/覆盖优化格局,加强区域生态安全研究,在GIS技术的支持下,利用景观分析和空间变异分析方法对北方13省(市、区)生态安全动态变化及其空间变异特征进行了分析。结果表明研究区生态安全指数具有较强的空间相关性。人类活动等随机因素对生态安全的作用强度在增大,但是结构性因素引起的空间相关仍然是该区生态安全空间分异的决定性因素。10年间研究区生态环境质量整体表现出下降趋势;空间上,中西部地区生态安全程度低于东部地区;13个省(市、区)的生态安全指数的变化表现为三种类型:先升后降型、先降后升型和持续下降型。  相似文献   

17.
蔡善柱  陆林 《地理科学》2019,39(3):415-423
选取1989~2015年地级市国家级经济技术开发区数量及主导产业面板数据,运用探索性空间数据分析(ESDA)技术,探讨国家级经济技术开发区及其产业空间格局演化特征。研究发现:国家级经济技术开发区整体经历探索阶段、推广阶段、完善阶段和升级阶段等4个阶段;空间格局演化体现出“点轴结构、T型结构、π型结构和网状结构”4种空间形态;空间扩散方式有“点-线-面”扩散、梯度扩散、等级扩散、邻近扩散、集聚扩散和升级扩散6种扩散模式;空间相关性整体呈波动起伏且逐渐上升态势,高-高集聚区从青岛-烟台逐渐演变为长三角、京津冀和福建沿海。 五大主导产业集中稳定,装备制造始终处于集聚态势,其余4个主导产业呈“分散-集聚”态势;三大类型产业空间布局演化与上述空间格局演化态势基本一致,空间集聚性整体呈“N型”变化态势,技术密集型产业集聚特征最为明显。  相似文献   

18.
土地利用/土地覆被变化及其生态环境效应研究是当前地理学全球变化研究的核心内容,而生态系统服务功能则是生态学、生态经济学研究的热点问题。作者利用滇西北生态脆弱区--永胜县1988年、1994年和1999年的TM遥感影像,采用景观生态学的空间格局指数分析研究区近10年来的土地利用动态变化特征,并以生态系统服务功能衡量相应土地利用类型的相对生态价值,评价区域土地利用/土地覆被变化的生态效应,尝试将二者有机结合起来。研究表明,全县景观总体构成表现为景观破碎度较高,斑块数目较多;林地和未利用地一直占很大比重,林地的不断增加与未利用地的迅速减少是研究时段内土地利用变化的突出特征;研究时段内全县土地利用变化带来了较好的生态效应,土地利用生态效益持续提高,并表现出了较大的空间差异。  相似文献   

19.
南京市土地利用效益耦合关系研究   总被引:2,自引:0,他引:2  
土地利用效益的耦合程度是评价土地利用是否科学合理的依据之一,也是土地可持续利用研究的重要内容。在分析土地利用社会经济效益与生态环境效益耦合关系的基础上,借助系统科学理论与方法,建立南京市土地利用效益间的耦合模型和相应指标体系,利用1999—2009年的统计数据对南京市土地利用效益耦合度进行了研究。结果表明:(1)自1999年以来,南京市土地利用社会经济与生态环境效益都处于上升状态。(2)土地利用社会经济效益与生态环境效益的耦合度α一直处于19.16°~70.65°之间,即处于协调发展阶段。但近几年土地利用效益耦合度居高不下,土地利用效益之间的矛盾依然存在。  相似文献   

20.
以托木尔区域为研究区,从景观生态学的角度,结合生态环境特征,选取分离度、分维数倒数、破碎度、植被覆盖指数和土壤侵蚀指数作为评价指标,探讨各景观类型区域生态环境脆弱度的空间分异规律,并依据生态环境的脆弱度等级结果进行区划。结果表明:(1)依据研究区海拔、坡度值划定地貌特征区,包括极高山、高山边缘区,南北部中山区,红层地貌区和南北部低山丘陵区;(2)建设用地的分离度最大,各景观类型的分维数倒数值差别不大,低覆盖度草地破碎度、景观类型脆弱度最大;(3)托木尔区域生态环境脆弱度指数具有强烈的空间自相关性,是自然因素和人为因素共同作用的结果;(4)区域生态环境脆弱度指数空间表现为“北低南高”的趋势,自然因素是影响生态环境高脆弱度区域(7~9级)的主导干扰因素;人类活动与自然因素共同作用于生态环境中脆弱度区域(4~6级);影响低脆弱度区域(1~3级)生态环境脆弱度的主要因素是人类活动;(5)根据研究区内生态环境脆弱度值,结合当地自然特征、社会经济发展现状,研究区可划分为保护区、限制开发区和可开发区,并对其实施差别化的政策管理与保护措施。  相似文献   

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