基于遥感数据的流域土壤侵蚀强度快速估测方法

以北京延庆县境内的妫水河流域为例, 提出了一种基于遥感数据的土壤侵蚀强度快速估测方法。首先, 利用遥感数据和植被指数模型提取流域内土地利用类型信息和植被覆盖度信息; 其次, 利用数字高程模型数据生成坡度图; 然后, 结合土壤侵蚀强度分级指标, 将坡度图与土地类型图、植被覆盖度图空间叠加, 判断和计算侵蚀强度等级, 结果获得了流域土壤侵蚀强度等级图; 最后, 计算了流域的年平均侵蚀模数。结果表明, 妫水河流域的土壤侵蚀以微度和轻度为主, 所占面积比例为74.88% , 极度和剧烈侵蚀很少, 不到总面积的2%。整个流域的年侵蚀模数估计为1 74611/ km ²·a。     

卫星遥感技术在永定河流域（河北）土壤侵蚀调查评价中的应用研究

利用Landsat-5TM图像,在分析土壤侵蚀影响因素的基础上,首先进行与土壤侵蚀相关密切的各单项要素的解译;其次,以土壤侵蚀在TM图像上的综合反映为标志进行基本侵蚀图斑的综合解译;第三步通过选定的的土壤侵蚀强度评判模型,对每个基本侵蚀图,由不同权重的各单项要素给出其分值,最后根据综合分值确定每个图斑的土壤侵蚀强度等级。研究结果表明,冀西北地区土壤侵蚀是非常严重的,以轻度侵蚀为下限的侵蚀区面积占全区面积的65％。两大地貌单元区相比,盆地区更严重于山地区。但多时相对比研究也表明,近十几年的治理工作取得了明显成效,土壤蚀的总趋势是向减缓方向发展。     

利用HJ-CCD影像的红壤丘陵区土壤侵蚀分析——以赣州市为例

针对南方红壤丘陵区水土流失严重这一问题,水利部为此在2014年实施了专门的水土流失综合治理技术标准(SL657—2014)。为精确评估红壤丘陵区土壤侵蚀状况及分析时空演变规律,在新的技术标准指导下,以赣州为例,采用RUSLE模型和HJ-CCD影像,定量分析了该区2008年和2013年土壤侵蚀及时空演变。结果表明:相比2008年,该区域土壤侵蚀状况有了一定程度改善,侵蚀总量由5 867.589t降到5 225.733t;坡度在15~30°是中度及以上侵蚀的主要区域,在250~350m高程范围内土壤侵蚀量达到最大,150~550m范围为土壤发生侵蚀的主要高程区域;赣州西南到东北区域生态环境依旧脆弱,兴国县侵蚀状况有所好转,上犹、崇义、会昌三县的土壤侵蚀呈进一步加剧趋势。     

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。     

济南山丘区地貌演化与水土流失研究

水土流失,其实是一种主要的侵蚀地貌演化过程。本文以戴维斯提出的地貌侵蚀循环学说为基础,把高程-面积分析法运用到流域地貌发育研究之中,把济南山丘区地貌发育阶段分为壮年期和老年期。各流域土壤侵蚀危险度平均值、土壤侵蚀强度综合指数的大小次序与其地貌发育阶段呈现良好的对应关系,说明尽管人类活动是加剧土壤侵蚀的主要原因,但地貌发育过程对土壤侵蚀的影响同样不可忽视。     

21世纪以来西安城乡梯度土地覆盖变化及对城市热岛影响时空特征

城市快速扩张导致城乡梯度土地覆盖发生显著的变化,引发不透水地表的增加,植被覆盖的减少,从而加剧了城市热岛强度。研究城乡梯度土地覆盖变化引起的城市热岛效应,并揭示城市热岛的时空特征及强度的变化,对城市规划建设、人居环境改善及提升城市生态系统服务功能具有重要的意义。基于Landsat系列4期影像,利用单窗算法反演西安市地表温度,计算热场变异指数得到热力场强度图并对其进行等级划分,结合土地利用/覆盖类型数据分析城乡梯度土地覆盖变化对城市热岛强度的影响。结果表明：①2000年西安市极强热岛效应区占研究区面积的10.58%,逐渐增加到2011年极强热岛效应区域的面积占比达到16.14%,而后到2015年降低为9.00%,整体上西安市城市热岛效应呈现出了先增长后降低的趋势;②2000年到2015年城乡建设用地面积增加了412.76 km2,极强热岛强度的范围随城市建成区的扩张逐年向外扩展;③无热岛效应区约70%位于耕地和林地,水域在无热岛效应中的占比也在逐年增多,从31%增加到了47%。不透水地表面积占比与地表温度有显著相关性,城乡梯度植被和水体面积的增加可以有效地缓解城市热岛强度。     

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.     

鞍山市生态资源与环境质量的遥感数据分析

利用美国陆地卫星资源Landsat TM遥感监测数据，参考相关图件，进行解译判别，监测鞍山市区及各县区土地类型、土地 退化类型，并结合水资源的调查结果，对鞍山市生态环境质量进行评价，分析结果表明，鞍山市全境存在一定程度的土壤侵蚀现 象，但基本上为微度侵蚀，重度侵蚀和中度侵蚀面积较小；鞍山市区和台安县生态环境状况指数一般，较适合人类生存，岫岩县和 海城市生态环境状况指数良好，生物多样性较好，基本适合人类生存。     

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%。     

近20 a若尔盖湿地水土流失变化的遥感评估

在若尔盖湿地以1989、2000、2005和2010年的Landsat TM/ETM数据为信息源提取土地覆盖以及植被覆盖度信息,结合ASTER DEM数据,在地理信息系统技术空间分析功能的支持下,依据水利行业《土壤侵蚀分类分级标准》(SL190-2007),通过叠加分析对研究区近20 a水土流失变化状况进行评估并分析了其与沼泽萎缩的关系。研究结果表明:若尔盖湿地土壤水力侵蚀面积广,但是程度轻;2000年以前水土流失程度加重,泥沙淤积是沼泽快速萎缩的原因之一;之后在相关生态环境建设和恢复措施作用下水土流失程度有所减轻,沼泽萎缩也呈减缓趋势。     

An agrometeorological–spectral model to estimate soybean yield,applied to southern Brazil

Soybean yield is modelled from data gathered from crops in Rio Grande do Sul State, Brazil. The model comprises an agrometeorological term, obtained by adjusting the multiplicative model of Jensen, modified by Berlato, and a spectral term, obtained from National Oceanic and Atmospheric Administration (NOAA) satellite images of the maximum Normalized Difference Vegetation Index (NDVI). The weather data used to calculate the relative evapotranspiration (ET _r /ET ₀) cover the period from 1975 to 2000, and the NDVI/NOAA images were obtained from 1982 to 2000. Application of the agrometeorological–spectral model produced better yield estimates (of about 5%) than Jensen's model, allowing the further generation of yield maps for the most significant soybean production regions within the Rio Grande do Sul State.     

Monitoring desertification and land degradation over sub-Saharan Africa

A desertification monitoring system is developed that uses four indicators derived using continental-scale remotely sensed data: vegetation cover, rain use efficiency (RUE), surface run-off and soil erosion. These indicators were calculated on a dekadal time step for 1996. Vegetation cover was estimated using the Normalized Difference Vegetation Index (NDVI). The estimation of RUE also employed NDVI and, in addition, rainfall derived from Meteosat cold cloud duration data. Surface run-off was modelled using the Soil Conservation Service (SCS) model parametrized using the rainfall estimates, vegetation cover, land cover, and digital soil maps. Soil erosion, one of the most indicative parameters of the desertification process, was estimated using a model parametrized by overland flow, vegetation cover, the digital soil maps and a digital elevation model (DEM). The four indicators were then combined to highlight the areas with the greatest degradation susceptibility. The system has potential for near-real time monitoring and application of the methodology to the remote sensing data archives would allow both spatial and temporal trends in degradation to be determined.     

Modelling soil loss rates in the Ethiopian Highlands by integration of high resolution MOMS-02/D2-stereo-data in a GIS

Landscape degradation by soil erosion has increased considerably in the Ethiopian Highlands since the deforestation of the natural mountain forests and the cultivation of large areas, resulting in a serious threat to the Ethiopian population. This investigation shows how to integrate remote sensing data into a geographical information system (GIS) for modelling soil loss rates. Stereoimage data of the MOMS-02/D2-sensor, tested during the Second German Spacelab-Mission D-2, served as main database. By application of the Universal Soil Loss Equation (USLE) thematic maps were produced, which emphasize the spatial impact of different soil erosion factors and show the expected dimensions of soil loss. The result shows that the integration of remote sensing data into a GIS offers various applications for resource management in developing countries.     

云南省土壤污染数据处理系统图表的生成

以Visual Basic(VB)和SQL Server 2000作为开发工具,以ArcGIS作为点位、等值面等地图制作平台来实现云南省土壤污染状况数据处理系统的图表生成和管理。该系统完成云南省土壤污染状况调查、统计及评价的数据处理,并将结果以Ex-cel表、各种统计图和地图的形式表现出来。图表的生成和管理具有应变能力强、内容自动更新、图表应用方便的优点,对图表的高效率生成及其应用发挥了重大的作用。     

Assessment of erosion hotspots in a watershed: Integrating the WEPP model and GIS in a case study in the Peruvian Andes

This paper presents a case study in assessment of erosion hotspots in an Andean watershed. To do this, we made use of an interface called Geospatial Modelling of Soil Erosion (GEMSE): a tool that integrates Geographical Information Systems (GIS) with the Water Erosion Prediction Project (WEPP) model. Its advantages are: (i) it is independent of any special GIS software used to create maps and to visualize the results; (ii) the results can be used to produce response surfaces relating outputs (e.g. soil loss, runoff) with simple inputs (e.g. climate, soils, topography); (iii) the scale, resolution and area covered by the different layers can be different among them, which facilitates the use of different sources of information. The objective of this paper is to show GEMSE's performance in a specific case study of soil erosion in La Encañada watershed (Peru) where the hillslope version of WEPP has been previously validated. Resulting runoff and soil loss maps show the spatial distribution of these processes. Though these maps do not give the total runoff and soil loss at the watershed level, they can be used to identify hotspots that will aid decision makers to make recommendations and plan actions for soil and water conservation.     

Short-term vegetation succession and erosion identified by airborne remote sensing of Westerschelde salt marshes,The Netherlands

The Westerschelde estuary is the only major uncontrolled estuary in the south of The Netherlands. More than 15?000 ships per year use it to access the Belgian port of Antwerp. A major dredging operation along the Westerschelde in the late 1990s has changed the tidal regime and increased tidal inundation of the salt marshes at high tide. Airborne remote sensing (CASI) has been acquired in 1998 and 2000 for three salt marsh sites in the Westerschelde estuary. An additional dataset exists for one site for 1993. The CASI data have been classified into maps of salt marsh vegetation. These provide an input for GIS-based modelling of sediment erosion/accretion. Maps of Normalized Difference Vegetation Index (NDVI) values allow change detection: successional change of salt marsh vegetation is clearly demonstrated. The 1993, 1998 and 2000 data show a successional trend between 1993 and 1998 that is, in part, reversing between 1998 and 2000. Data also showed significant erosion of the salt marsh edge. Data are being used to extrapolate field measurements and help produce sediment budgets for the individual salt marshes.     

Application of Hyperion data to land degradation mapping in the Hengshan region of China

Hyperspectral remote sensing is a promising tool for analysing and evaluating the risk of increasing land degradation. The aim of this paper was to introduce a methodology for mapping land degradation using Hyperion data. Salinization and wind erosion (desertification) are alarming signs of land degradation in Hengshan County, in the northern Shanxi Province of China. The Soil-Adjusted Vegetation Index (SAVI), Desertification Soil Index (DSI), Soil Organic Material Index (SOMI), Soil Ferric Oxide Index (SFOI) and Normalized Difference Water Index (NDWI) were chosen as the evaluation factors to set up the assessment system, and the extent of land degradation in the study area was divided into four grades: none, slight, moderate and high. Samples of each grade were used for overlay analysis in ArcGIS software using the five bands of the hyperspectral indices as inputs. Then, the land degradation maps were generated using support vector machine (SVM) and artificial neural network (ANN) approaches. We found that the SVM results were better than the ANN, with an overall accuracy of 0.93 for the SVM as compared to 0.88 for the ANN. The main advantage of the SVM is attributed to the transformation of the complicated learning problem into a high-dimensional simplified linear problem, which can overcome some flaws in other mechanical learning methods, such as the ‘over-study’ problem for ANN. It is concluded that this type of procedure for estimating the extent of land degradation is feasible and the SVM algorithm is an efficient method for mapping land degradation.     

Development of a geospatial screening tool to identify source areas of windblown dust

Soil properties and air-mass backward trajectories were integrated into a geographical information systems (GIS) tool to identify geographical regions that were likely to have significant influence on dust concentrations at Class I national parks and wilderness areas in US. The Windblown Dust Index (WDI) was introduced by spatial analysis of wind erosion and land use/land cover data for North America to identify potential area sources of windblown dust. The spatial probability density maps of backward trajectories were utilized to determine the number of trajectory points that passed near a grid cell at speeds higher than a specified threshold value. Analysis of data for the Salt Creek and White Mountain wilderness areas highlighted the significant potential of both local and regional sources of windblown dust at the two sites, with evidence for seasonal variation. These data are useful in evaluating the importance of windblown dust source areas and developing cost-effective targeted studies and/or mitigation strategies.     

Runoff mapping using WEPP erosion model and GIS tools

Soil erosion, associated with environmental impacts and crop productivity loss, is usually considered the most impacting of surface hydrology processes. Runoff plays a major role in the erosion process, but it is also important by itself as it directly influences several surface hydrologic processes. In this paper, a computer interface (Erosion Database Interface, EDI) is described that allows processing the surface hydrology output database of the Water Erosion Prediction Project (WEPP) erosion prediction model, resulting in a georeferenced estimation of runoff. WEPP output contains non-georeferenced daily information about estimated runoff at the lower end of each Overland Flow Element. EDI, when running with WEPP, allows extracting WEPP-calculated runoff values, transforming them into annual means and relocating them in a georeferenced database readable by Geographic Information Systems (GIS). EDI was applied to a 1990 ha watershed in southeast Brazil, with vegetation of mainly sugarcane, forest, and pasture. A 100-year climate simulation was used as input to WEPP, and erosion values were calculated at about six points per hectare and interpolated to a raster format. EDI was successful in preparing the database for automatic calculation of erosion and hydrologic parameters with WEPP and to restore georeferences to mean annual accumulated runoff data that were imported in the GIS as a vector database. Of all the resulting maps, the runoff map is the one that integrates all of the input parameters required for WEPP simulation, thus reflecting not only the physical environment but also crop growth and management and tillage operations. A very small correlation between runoff and erosion shows them to behave independently. Moreover, it is concluded that on analyzing runoff related to agricultural management, georeferenced runoff studies are especially important. In this context, EDI may be a useful tool to assess the effect of tillage and crop management on runoff production.     

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.