浙江省低丘红壤区土壤侵蚀评价研究

本文以浙江省低丘红壤区为研究对象,利用卫星遥感影像构造削弱阴影等干扰的FCD模型,和混合像元法计算植被覆盖度的方法,进行水土流失研究.根据水利部颁布的<土壤侵蚀分类分级标准>,结合植被覆盖度、坡度、利用现状等因子进行土壤侵蚀强度评价.研究结果表明目前红壤区内植被覆盖情况良好,覆盖度基本在30%以上;整体水土流失程度较轻,但是耕地等农用地的侵蚀情况较为严重,特别足红壤区内耕地的强度侵蚀的面积占其总面积的17.65%.另外,耕作侵蚀也是土壤侵蚀非常重要的凶素,在估算土壤侵蚀强度的时候也应重视.目前浙江省需要补充大量耕地以满足社会发展的需要,鉴于红壤水土流失易发的特点,在低丘红壤开发时要重视水土流失的预防和控制.     

基于MODIS的水土保持动态监测系统的设计与实现

介绍基于MODIS数据的水土流失动态监测系统的设计过程和实现方式.系统利用MODIS遥感影像计算归一化植被指数得出植被覆盖度图,与土地利用状况图和坡度图进行叠加分析处理,根据一定的规范标准得到研究区域内某一时刻的土壤侵蚀状况图,对水土流失状况及流失程度进行动态监测,为预防监督工作和水土保持方案的制定提供信息支撑.     

基于RS与GIS的大尺度水土流失分级制图

以长春市双阳区鹿乡镇为例，选用SPOT5的遥感数据、DWG全要素地形图，运用遥感软件提取植被指数并进行密度分割，确定植被覆盖度；用地理信息系统软件提取地形坡度信息，并对地形坡度进行分级。然后根据植被覆盖度、地形坡度和土地利用类型几个水土流失强度因子，确定水土流失强度的分级指标，生成水土流失等级强度图。为水土流失监测、治理提供依据。
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京津风沙源治理工程区LUCC及土壤风蚀强度动态遥感监测研究

以遥感手段监测京津风沙源治理工程区土地利用/覆盖变化及土壤风蚀强度,分析了工程区LUCC及土壤风蚀时空格局特征及关系。结果表明:工程实施前后,LUCC及土壤风蚀强度差异明显。近30a,LUCC过程主要表现了由耕地开垦向生态退耕还林、草转变,伴随生态恢复和沙化有效抑制态势;耕地总体表现出先增加后减少态势,耕地面积1990～2000年增加面积是2000～2015年减少面积的1.9倍;林地总体呈增加态势;2000～2015年耕地转化为林地和草地面积分别为446.1km2和1 129.3km2,西部最为明显;建设用地面积扩张明显;未利用地呈减少趋势,转换类型以沙地向草地转化为主,面积为1 493.1km2。京津风沙源治理工程区土壤风蚀侵蚀模数整体呈下降趋势,生态工程实施后改善趋势明显(P0.01);总体上,东部、南部地区以高覆盖、中覆盖草地类型为主的地区土壤风蚀量小;浑善达克沙地治理区土壤风蚀量较大,但总体呈减少趋势。不同土地利用/覆盖类型对土壤风蚀强度影响较大,土壤风蚀模数依次为沙地低覆盖度草地中覆盖度草地旱地灌木林水田高覆盖度草地其他林地疏林地有林地;低覆盖度向高覆盖度草地类型转化有效抑制土壤风蚀量(减少66.12%),植被覆盖度的增加有效降低土壤风蚀模数;沙地周边区域,高/中覆盖度向低覆盖度草地类型转换过程中,土壤风蚀量呈增加(58.26%)态势,草地转化为沙地、旱地土壤风蚀量增加。     

遥感与GIS在准格尔旗土壤侵蚀监测中的应用

以内蒙古准格尔旗为例,利用TM图像及相关辅助数据,通过GIS软件ARC/INFO、遥感软件ERDAS IMAGINE 8.5,对影像进行格式转换、人机交互解译等处理,得到准格尔旗土壤侵蚀的结果数据。结果表明,准格尔旗风力侵蚀,水力侵蚀总体上仍比较严重,且以水力侵蚀为主。水力侵蚀与风力侵蚀强度侵蚀以上所占比例分别为68.39%和48.45%。     

黄河流域甘肃片水土保持遥感判读特征研究

以黄河流域甘肃片水土保持遥感普查为例,分析了土壤侵蚀六项主要影响因子:侵蚀类型、侵蚀强度、地表组成、地貌类型、植被覆盖及地面坡度。通过研究各因子在TM影像上的分布、形状、纹理等识别特征,探讨了水土保持影响因子在遥感判读中的信息提取方法。并具体应用到2000年黄河流域甘肃片遥感普查数字化工作中,提出了各因子遥感判读特征分类系统。     

江西省兴国县土壤侵蚀动态演变趋势分析

利用1958、1975、1982、2000年4期的土壤侵蚀强度等级图,空间配准及矢量化后,制成栅格分类图。在IDRISI 的CROSSTAB模块下分别计算了1958年到1975年,1975年到1982年及1982年到2000年的土壤侵蚀等级转换矩阵。根据该矩阵对兴国县土壤侵蚀的情况分期地进行了定量分析。结果表明:在研究的时期内,兴国县的土壤侵蚀经历了三个主要过程:1958年到1975年的侵蚀加剧期,1975年到1982年的自然恢复期,1982年到2000年的全面恢复期。到2000年,强度侵蚀的面积明显减少,无明显侵蚀的面积已达到全县面积的74.7%,严重土壤侵蚀状况已基本得到了控制。     

米脂县土壤侵蚀量遥感测量与分析

黄土高原严重的土壤侵蚀闻名于世界。而说明其严重程度的具体侵蚀数据,一直是由水文站根据河水含沙量推算出的输沙模数表示的。水文站往往因控制流域面积较大,流域范围内不同地段的自然条件不同,侵蚀强度并不一样。这样的数据并不反映各地理单元土壤侵蚀的具体原因和过程,不利于深入研究黄土高原土壤侵蚀的机理,并据此提出相应的防治措施。本项研究试图借用航空立体测量的方法,通     

基于直方图与像元分解模型的森林覆盖度遥感估算

森林覆盖度是能够勾描出林分边界的森林覆盖率,定量化的覆盖度信息可体现其水平尺度的时空分异特性。像元分解模型在覆盖度遥感估算中得到了广泛应用,但仍然有很多问题,如很难找到一种树冠覆盖度的纯光谱端元,从而难以高精度地估算树冠覆盖度。为此,基于像元分解模型,结合使用土地利用和土壤类型数据,提出利用直方图法确定模型中不同类型植被——土壤端元参数,对区域尺度森林覆盖度进行估算,并利用三峡库区的历史野外161个样点的实测覆盖度数据进行验证,发现R~2达到0.74～0.85,计算结果比较满意。该方法将为区域尺度高分辨率森林覆盖度的遥感估算提供借鉴。     

南方丘陵区植被覆盖度遥感估算与时空变化研究——以福建省永定县为例

植被覆盖度是生态环境监测的重要指标,而复杂地形因素影响对山地植被遥感信息准确提取。基于Landsat-8OLI遥感数据,分别采用像元二分模型和线性混合光谱分解法,在对比分析植被覆盖度的地形敏感性基础上,选择山地植被指数(NDMVI)估算了1992、2002和2014年永定县的植被覆盖度,并分析其变化。结果表明:1基于山地植被指数(NDMVI)的覆盖度估算模型的地形敏感性最弱,更适合于南方丘陵山地的植被覆盖度遥感反演;2永定县总体植被覆盖度较高,平均植被覆盖度达77.99%以上,高覆盖度区占59.73%以上,22年内植被覆盖度经历了先提高再下降的过程;3在空间上,高坎抚、金丰和西部片区的植被覆盖度较低,动态变化较明显。永定县金丰片区植被覆盖度明显提高;而近12年内高坎抚片区因矿业开采活动对生态环境的破坏,植被覆盖度降低幅度大,且变化面积较大。     

Study on Dynamic Remote Sensing Monitoring of LUCC and Soilwind Erosion Intensity in the Beijing-Tianjin Sandstorm Source Control Project Region

The Land Use/Cover Change(LUCC) and soil wind erosion intensity of the Beijing\|Tianjin sandstorm source control project region were monitored by remote sensing.The spatial and temporal patterns of LUCC and soil wind erosion in the project region were analyzed.The results showed that there was significant difference in LUCC and soil erosion intensity before and after the project was implemented.In the recent 30 years,the LUCC process mainly manifested the change from cultivated land reclamation to ecological conversion of farmland to forest and grass,with the ecological restoration and desertification effectively inhibited.The overall arable land showed an increase and then decreased.The area of arable land increased from 2000 to 2015,the area of cultivated land converted to forest and grassland was 446.10 km² and 1 129.32 km²,with the most obvious in the west;the area of land for construction expanded obviously;the trend of unutilized land decreased significantly The type of conversion is dominated by grassland conversion to grassland with an area of 493.12 km².The erosion-mitigating modulus of soil erosion in the project region with wind-blown sand control decreased overall,especially after the implementation of ecological engineering (p<0.001).The eastern and southern areas are covered with high-coverage grassland and soil wind erosion in the area with the main type is small;Soil wind erosion in the Hunshandake sandy land is larger,but the overall trend is decreasing.Different land use/cover types have a greater impact on soil wind erosion intensity.The order of soil wind erosion modulus is Sandy land> Sparse grass> Moderate grass>dryland> Shrub>Paddy>Dense grass> Other woods> Sparse woods> Forest;The conversion of low coverage to high coverage grassland types effectively inhibited soil erosion (-66.12%),and the increase of vegetation coverage effectively reduced soil erosion.The soil wind erosion increased (58.26%) in the surrounding area of sandy area,the soil wind erosion increasedduring the conversion process of low coverage grassland type,and the grassland was converted into sand,and the wind erosion in the dry land increased.     

Evaluation of sediment yield by using remote sensing and GIS: A case study from the Phulang Vagu watershed,Nizamabad District (AP), India

The primary objective of this paper is to identify soil erosion zones and to suggest appropriate measures for control of soil erosion using remote sensing, GIS and conventional technique in the Phulang Vagu watershed in the Sriramsagar catchment area of Andhra Pradesh. The digital imagery data of the study area is obtained from the IRS-IC (LISS-III) satellite whereas the toposheets and rainfall data of the study area were obtained from the Survey of India. Satellite images were interpreted to prepare land use/land cover maps by using ERDAS image processing system. Out of 725.983 km 2 of the study area, about 301.435 km 2 is wasteland which is identified as susceptible for soil erosion. Toposheets of the study area were used to prepare drainage and slope maps. Drainage pattern is mainly dendritic with a density of 1.26 km -1 and the stream slope is 0.00614. The arithmetric average method is used to find average annual rainfall. The above parameters were used to calculate the amount of soil erosion from the catchment area. It was found that 882.389 m 3 km -2 year -1 of soil is being eroded from the catchment area which is more than the value adopted in the design of Sriramsagar reservoir. Therefore soil conservation measures such as vegetative cover in the waste land are needed and 12 check dam sites have been proposed by superimposing drainage map and slope map in conjunction with land use/land cover map. With these soil conservation measures, the soil erosion could be kept within the design value of Sriramsagar reservoir.     

基于遥感和GIS的区域土壤侵蚀变化与人类活动关系研究

土壤侵蚀作为全球性的主要环境问题之一,受人类活动的影响日益强烈。在区域尺度上研究人类活动与土壤侵蚀变化的关系,对土壤侵蚀防治宏观决策具有重要意义。通过构建人类活动程度指数,从栅格尺度上分析了人类活动程度对土壤侵蚀变化的影响规律,进而从人口变化、土地利用变化和人类活动对植被覆盖影响程度等多角度综合分析,揭示人类活动对土壤侵蚀变化的驱动机制。结果发现,江西省1990年土壤侵蚀模数平均值841 t/（km²·a）,2018年减少到338 t/（km²·a）,土壤侵蚀明显缓解。平均人类活动程度指数由0.005增加到0.014,空间上呈现出以城市为中心向外辐射状的增加态势;偏远山地丘陵区,人类活动程度变化不大。20 a来,研究区土壤侵蚀的发生有由山地丘陵区向城市及周围地区转移的趋势。远离城市的偏远山地丘陵区,农村人口压力的减弱以及合理的土地利用转变促进江西省植被恢复,进而缓解土壤侵蚀;坡度缓和的城市及周边地区因人类活动程度的显著增强,土壤侵蚀有所加剧。     

Changes in the soil erosion status in the middle and lower reaches of the Yangtze River basin from 2001 to 2014 and the impacts of erosion on the water quality of lakes and reservoirs

ABSTRACT

The revised universal soil loss equation (RUSLE) was used to obtain the soil erosion intensity distribution in the middle and lower reaches of the Yangtze River basin (MLYB), where the input data included a digital elevation model (DEM) and Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing products. Changes in the soil erosion intensity throughout the MLYB were analysed from 2001 to 2014, and the potential influences of these changes on the local water quality of lakes and reservoirs were revealed. This investigation is the first to reveal the spatial and temporal changes in soil erosion throughout the MLYB. The results indicated that from 2001 to 2014, most of the MLYB was characterized by slight and light soil erosion levels, whereas relatively few areas exhibited intensive to severe soil erosion. Soil erosion in the MLYB displayed a decreasing trend from 2001 to 2014; over 80% of the region displayed a decreasing soil erosion intensity change rate, indicating that soil conservation in most of the MLYB has improved over the past 14 years. However, 12.8% of the area presented an increasing change rate, and the region with the maximum increasing change rate was located mainly in the lower Yangtze basin. Furthermore, spatial heterogeneities were found in the soil erosion intensities throughout the MLYB: soil erosion improved in the upper and middle regions of the MLYB, whereas soil erosion worsened in the lower regions of the MLYB. Among the sub-basins of the MLYB, obvious soil erosion occurred most frequently in the Hanjiang basin and least frequently in the Taihu basin. A driving force analysis showed that the influence of precipitation on soil erosion is more evident than that of human activities in all sub-basins except the Dongting basin. A correlation analysis between soil erosion and water turbidity/water transparency showed that 45.9% of the decreasing water turbidity is correlated with decreasing soil erosion and that 42.5% of the increasing water turbidity might be influenced by increasing soil erosion. Decreased soil erosion might be responsible for the improved water transparency for 50% of the lakes, whereas increased soil erosion is correlated with a decrease in water transparency for over 50% of the lakes.     

土壤侵蚀调查中的遥感应用综述

土壤侵蚀引起土壤肥力下降、土地退化及荒漠化和生态环境恶化等一系列区域性和世界性的重大环境问题。中国是土壤侵蚀最严重的国家之一。遥感是进行环境和灾害动态监测的有效技术手段。自从20世纪70年代以来．人们就开始应用遥感技术进行土壤侵蚀的调查。对遥感技术在土壤侵蚀调查中的应用方法进行概括和汇总，分别是影像判读法、指数提取法、图像分类法、光谱分解和正射影像DEM提法等方法，分析不同方法之间的优缺点以及它们各自的适用范围，并结合当前研究的热点问题，指出未来研究的重点及趋势。     

遥感和GIS辅助下的祖厉河流域土壤侵蚀空间变化分析

以遥感数据和观测数据为数据源,基于改进的SEMMED土壤侵蚀模型,对祖厉河流域1999年和2001年土壤侵蚀的空间变换进行了模拟和对比。结果表明,流域土壤侵蚀最严重的区域主要集中在葛家岔站点附近、草滩站附近和北部葛家寨和靖远一带,流域中南部的土壤侵蚀通常小于北部。在北部的屈吴山,以及与宁夏交界的月亮山还有华家岭由于植被覆盖度较高,很好的起到了减少径流,抑制土壤侵蚀的作用。降水的年际差异导致本区的土壤侵蚀年际差异较大。     

Remote Sensing Estimation of Forest Coverage based on Histogram and Pixel Decomposition Model

Forest coverage is the percentage of forest cover for hooking out the forest stand boundary,and quantitative coverage information can be used for describing the temporal and spatial variability of vegetation in the horizontal scale.Pixel decomposition model has been widely used in remote sensing estimation of vegetation coverage.However,there are still many problems.For example,it is difficult to find a pure spectrum of tree canopy coverage to estimate the crown coverage with high accuracy in forest vegetation applications.In this paper,combining land use and soil type data,it is proposed to determine the endmember parameters of the different vegetation-soil types by using the histogram method based on pixel decomposition model for estimating the regional scale forest coverage in the Three Gorges.And the results were verified using the 161 samples of field data in the Three Gorges Reservoir area,R² was found to be 0.742 4~0.853 6,the estimated results are satisfactory.This method will provide a reference for remote sensing estimation of high-resolution forest coverage at regional scale.     

Landslide hazard and risk analyses at a landslide prone catchment area using statistical based geospatial model

This paper presents the application of remote sensing techniques, digital image analysis and Geographic Information System tools to delineate the degree of landslide hazard and risk areas in the Balik Pulau area in Penang Island, Malaysia. Its causes were analysed through various thematic attribute data layers for the study area. Firstly, landslide locations were identified in the study area from the interpretation of aerial photographs, satellite imageries, field surveys, reports and previous landslide inventories. Topographic, geologic, soil and satellite images were collected and processed using Geographic Information System and image processing tools. There are 12 landslide-inducing parameters considered for the landslide hazard analyses. These parameters are: topographic slope, topographic aspect, plan curvature, distance to drainage and distance to roads, all derived from the topographic database; geology and distance to faults, derived from the geological database; landuse/landcover, derived from Landsat satellite images; soil, derived from the soil database; precipitation amount, derived from the rainfall database; and the vegetation index value, derived from SPOT satellite images. In addition, hazard analyses were performed using landslide-occurrence factors with the aid of a statistically based frequency ratio model. Further, landslide risk analysis was carried out using hazard map and socio-economic factors using a geospatial model. This landslide risk map could be used to estimate the risk to population, property and existing infrastructure like transportation networks. Finally, to check the accuracy of the success-rate prediction, the hazard map was validated using the area under curve method. The prediction accuracy of the hazard map was 89%. Based on these results the authors conclude that frequency ratio models can be used to mitigate hazards related to landslides and can aid in land-use planning.