共查询到20条相似文献，搜索用时 359 毫秒
1.
遥感和GIS支持下的分布式融雪径流过程模拟研究 总被引：2，自引：0，他引：2
基于遥感(RS)和地理信息系统(GIS)技术,设计和构建了一个分布式融雪径流模型,整个分布式融雪径流过程的模拟计算基于能量平衡和水量平衡,由分布式栅格融雪过程、分布式栅格产流过程以及分布式栅格汇流过程组成,融雪以及产汇流过程全部基于栅格尺度,全面实现了融雪过程的分布式模拟.分布式栅格融雪过程中对"度日法"加以改进,引入了"单元时段"的概念,从而得到了"度分融雪模型";针对融雪过程中颇为复杂的冻融反复性难题,提出了旨在解释积雪冻融反复性物理机制的"冻融系数"的重要概念,对于准确把握融雪过程的物理机制具有重要意义.同时基于GIS开发了分布式融雪径流模拟系统,为分布式融雪径流模型的运行提供了平台和技术支持,二者均为融雪洪水预警决策支持系统的核心模块部分.基于由MODlS等遥感数据得到的积雪信息、地表温度等下垫面信息,基础地理信息数据如DEM及其空间分析数据和大量野外同步观测数据(积雪信息、气象数据),对典型研究区新疆军塘湖流域2006年春季典型融雪期(2006-03-06,11:00-2006-03-10,11:00)内的洪水过程进行了模拟,模拟结果精度较高,平均精度0.82,达到了融雪洪水预警预报的业务需求标准. 相似文献
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流域栅格河网提取是数字地形分析的一个重要应用。为减少数字高程模型(DEM)预处理而产生的伪河道及平行河道,提出基于并行化多流向策略的栅格河网提取算法。通过水流传输矩阵模拟水量的自然流动过程,可直接应用于原始DEM。从河网空间形态和算法运行效率两方面与串行MFD算法、R&N算法及D8算法进行对比,结果表明,多流向策略得到的河网与实际地形形态更加吻合,使用并行策略后,算法的效率比也较其他算法有明显提升。 相似文献
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基于空间分布式汇流时间方法的流域洪水模拟模型采用SCS模型,进行空间分布净雨强度计算。格网单元的流向用流域的DEM来确定,出口的直接径流就是在各个汇流时间段内到达出口的所有格网单元的体积流之和。模型结构简单、参数物理意义明确。基于对该模型的原理和运行流程的描述,以浙江皎口水库流域为例,对该流域的1979~2001年中的6场洪水的径流过程进行模拟。结果显示,皎口水库流域小时径流模拟值与实测值曲线拟合度较好,水量拟合指数平均值为1.04,平均模型效率系数为0.68。 相似文献
4.
流域地形自动分割研究 总被引：26，自引：0，他引：26
本文提供了基于栅格数字高程模型（ＤＥＭ）提取流域空间结构,进行流域自动分割的技术方法。该方法包括地貌形态结构定义、流域结构定义和算法设计３个部分。基于本文设计的算法,可以从ＤＥＭ提取完整的汇流网络和分水线网络,两者组成的多边形集把流域分割成具有拓扑结构的多个子汇流区,这个子汇流区集作为存贮流域信息的基本地貌单元,是流域信息进入地学数据库的框架,也是进行空间分布式机理──过程流域分析模型的基础。并以山西离石黄土丘陵沟壑区的王家沟流域为试验区,获得了较为满意的结果。 相似文献
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《武汉大学学报(信息科学版)》2016,(12)
均一化迭代是基于栅格数据的洪水演进模拟常采用的迭代策略,存在设定迭代步长与栅格单元实际所需时间不一致的问题,直接影响到栅格单元水位、流量的计算精度。针对该问题,提出了一种双层异步迭代策略。外层迭代控制洪水演进时刻,内层迭代则通过分析不同栅格单元洪水的流速特征,实现迭代步长及迭代次数的自适应设定。采用商用FloodArea软件、均一化迭代算法及双层异步迭代算法,分别对福建省万安流域暴雨洪水历史数据进行模拟。该算法模拟结果的平均误差比FloodArea小0.361m,比均一化迭代算法小0.654m,说明该算法能有效提高洪水演进模拟的整体精度。 相似文献
8.
针对紧急条件下的溃坝洪水演进模拟实时要求高、灾情资料相对匮乏的问题,文章提出了一种基于栅格数据的水动力学溃坝洪水演进模拟算法。算法以栅格地形为基础,采用水动力学原理和GIS地形分析技术相结合的方法进行多次迭代计算。利用曼宁公式计算栅格单元间的流量,通过分析不同栅格单元洪水的流速特征,自适应计算迭代步长和计算次数,通过确定栅格间的洪水演进顺序,实现溃坝后洪水演进速度、淹没范围和水深的动态预估。选用安徽省王家坝蓄洪过程进行实验和对比验证。结果表明,该方法具有输入数据少、算法简单、计算速度快等特点,其模拟过程与历史灾情基本吻合,能够适应应急环境下的洪水演进模拟需要。 相似文献
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基于Monte Carlo方法的不确定性地理现象可视化 总被引：2，自引：0，他引：2
艾廷华 《武汉大学学报(信息科学版)》2004,29(3):239-244
应用Monte Carlo方法伪随机数模拟表达随机过程现象的数学方法，并结合粒子系统模型提出了一种地理现象空间分布不确定性特征的动画可视化方法。通过栅格单元的随机运动，从视觉上表达现象分布在空间定位、属性特征上的不确定性、模糊性，同时由Monte Carlo方法控制随机过程中现象分布的统计规律。 相似文献
11.
选取合适的评价单元是泥石流易发性评价的关键,为探索斜坡单元不同划分方法对泥石流易发性评价结果的影响,本文以泥石流多发地东川区为例,对比分析了水文分析法和曲率分水岭法两种斜坡单元划分方法在泥石流易发性评价中的效果。首先在解译泥石流点的基础上,采用不同划分方法的斜坡单元作为评价单元,然后对初步选取的指标因子进行多重共线性和贡献率分析,以完善指标因子体系,最后构建基于BP神经网络的泥石流易发性评价模型。结果表明,泥石流极高和高易发区主要集中分布于研究区小江河谷和金沙江南岸,该地区地质环境脆弱,危险性较高。基于曲率分水岭法的易发性模型AUC值为0.865 8,高于水文分析法的0.815 3,表明采用曲率分水岭法划分的斜坡单元更适用于研究区泥石流易发性评价。 相似文献
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DEM数据是流域水文分析和模拟的基础，不同DEM分辨率尺度深刻影响着水文分析和水文过程模拟的结果。本文基于机载LiDAR获取的DEM数据，分析了不同分辨率LiDAR DEM在坡度提取、水文指数分析和流域特征参数提取中的差异及产生原因；基于SWAT分布式水文模型模拟研究了不同分辨率DEM数据的水文效应。研究结果表明：随着DEM分辨率的降低，坡度平均值减小，TWI平均值增大，SPI平均值减小，LSF均值先增大后减小，当分辨率为10 m时，LSF取得最大值；SWAT模型模拟结果表明，随分辨率的降低、坡度值的变小，地形湿度指数变大，蒸散发量增加，地表径流深减小，而土壤渗漏量与地下径流量则是先减小后增加，出现极值时DEM分辨率为10 m，与LSF出现极值时一致。 相似文献
13.
Praveen G. Saptarshi Rao Kumar Raghavendra 《Journal of the Indian Society of Remote Sensing》2009,37(4):693-704
The planning of conservation measures to conserve water and soil resources taking hydrological planning unit as micro-watershed
is considered to be effective. The automated watershed delineation technique using the spline interpolated filled digital
elevation model (DEM) is effective in converging slopes of the area in which the stream patterns match with the manually digitized
stream patterns of the topographical map. The various vector spatial layers like the slope/aspect, land-use/land-cover, runoff
potential, soil erosion potential and the associated attribute information governing the criteria for different conservation
structures can act as input layers in integrated spatial analysis module in GIS environment to evolve derived layers indicating
the locations of conservation sites meeting the requisite criteria. The reliability of suitable conservation sites suggested
out of integrated spatial GIS analysis could be ascertained using the multi criteria analysis incorporating the various factors
controlling soil erosion process in the micro-watershed groups. The details of the above work are discussed in the paper. 相似文献
14.
Impact of Climate Change on Runoff of the Major River Basins of India Using Global Circulation Model (HadCM3) Projected Data 总被引：1，自引：0，他引：1
Praveen K. Gupta Sushma Panigrahy Jai Singh Parihar 《Journal of the Indian Society of Remote Sensing》2011,39(3):337-344
The effects of climate change on hydrological regimes have become a priority area for water and catchment management strategies.
The terrestrial hydrology driven by monsoon rainfall plays a crucial role in shaping the agriculture, surface and ground water
scenario in India. Thus, it is imperative to assess the impact of the changing climatic scenario projected under various climate
change scenario towards the hydrological aspects for India. Runoff is one of the key parameters used as an indicator of hydrological
process. A study was taken up to analyse the climate change impact on the runoff of river basins of India. The global circulation
model output of Hadley centre (HADCM3) projected climate change data was used. Scenario for 2080 (A2 scenario indicating more
industrial growth) was selected. The runoff was modeled using the curve number method in spatial domain using satellite derived
current landuse/cover map. The derived runoff was compared with the runoff using normal climatic data (1951–1980). The results
showed that there is a decline in the future climatic runoff in most of the river basins of India compared to normal climatic
runoff. However, significant reduction was observed for the river basins in the eastern region viz: lower part of Ganga, Bahamani-Baitrani,
Subarnrekha and upper parts of the Mahanadi. The mean projected runoff reduction during monsoon season (June–September) were
18 Billion Cubic Meter (BCM), 3.2 BCM, 3.5 BCM and 5.9 BCM for Brahmaputra-Barak Subarnrekha, Subarnarekha and Brahmini-Baitrani
basin, respectively in comparison to normal climatic runoff. Overall reduction in seasonal runoff was high for Subarnrekha
basin (54.1%). Rainfall to runoff conversion was high for Brahmaputra-Barak basin (72%), whereas coefficient of variation
for runoff was more for Mahanadi basin (1.88) considering the monsoon season. Study indicates that eastern India agriculture
may be affected due to shortage of surface water availability. 相似文献
15.
数字流域中的WebGIS设计与实现 总被引：1，自引：0，他引：1
研究了基于WebGIS体系的数字流域系统的建设，提出了以渭河流域为试点的数字流域建设的设计及实现方案，实现了该流域信息的可视化及地图交互操作。 相似文献
16.
Dominic Mazvimavi Saskia L.G.E. Burgers Alfred Stein 《International Journal of Applied Earth Observation and Geoinformation》2006
The selection of basin characteristics that explain spatial variation of river flows is important for hydrological regionalization as this enables estimation of flow statistics of ungauged basins. A direct gradient analysis method, redundancy analysis, is used to identify basin characteristics, which explain the variation of river flows among 52 selected basins in Zimbabwe. Flow statistics considered are mean annual runoff, coefficient of variation of annual runoff, average number of days per year without flow and selected percentile flows. Basin characteristics investigated are those likely to reflect climatological, topographical and hydrogeological influences including that of land cover on river flows. The first ordination axis of flow statistics is strongly correlated with mean annual precipitation, mean annual potential evaporation and median slope. This ordination axis explains 64% of the variation of selected flow statistics among the selected drainage basins. The proportions of a basin under cultivation, and that with grasslands are correlated with the second ordination axis, which explains 6% of the variation of selected flow statistics. Mean annual precipitation is the most important basin characteristic, and this alone explains 50% of the variation of flow statistics. Median slope is the second most important basin characteristic. Proportions of a basin underlain by different lithological types had no effect on flow characteristics of selected basins. The paper has demonstrated the ability of redundancy analysis to identify basin characteristics that explain the variation of river flows among basins, including estimating the relative importance of these basin characteristics. 相似文献
17.
M P Tripathi R K Panda S Pradhan S Sudhakar 《Journal of the Indian Society of Remote Sensing》2002,30(1-2):39-52
This study was conducted for the Nagwan watershed of the Damodar Valley Corporation (DVC), Hazaribagh, Bihar, India. Geographic Information System (GIS) was used to extract the hydrological parameters of the watershed from the remote sensing and field data. The Digital Elevation Model (DEM) was prepared using contour map (Survey of India, 1:50000 scale) of the watershed. The EASI/PACE GIS software was used to extract the topographic features and to delineate watershed and overland flow-paths from the DEM. Land use classification were generated from data of Indian Remote Sensing Satellite (IRS-1B—LISS—II) to compute runoff Curve Number (CN). Data extracted from contour map, soil map and satellite imagery, viz. drainage basin area, basin shape, average slope of the watershed, main stream channel slope, land use, hydrological soil groups and CN were used for developing an empirical model for surface runoff prediction. It was found that the model can predict runoff reasonably well and is well suited for the Nagwan watershed. Design of conservation structures can be done and their effects on direct runoff can be evaluated using the model. In broader sense it could be concluded that model can be applied for estimating runoff and evaluating its effect on structures of the Nagwan watershed. 相似文献
18.
河网汇水区域的层次化剖分与地图综合 总被引：2，自引：0，他引：2
对于具有网络状结构的河系数据的综合化简,判断河流分支在河网中的重要性需要考虑三个层次的结构信息:全局范围内的空间分布模式;局域环境下的分布密度;单条河流的几何特征。为提取这些结构化信息,本文基于网络分析运用Delaunay三角网模型建立了各级河流分支汇水区域的层次化剖分模型,其基本思想是将汇水区域划定当作“空间竞争”问题来求解,运用类似于Voronoi图的空间等剖分几何构造表达“袭水”过程,在各支流子系统内部及其环境之间通过Delaunay三角网骨架线确定汇水区域的分水岭。基于该层次剖分模型可计算河流分布密度、相邻河流间距、汇水范围及层次关系,进而推算出河系网中每一条河流的重要性系数,实现不同尺度下河流的综合选取。 相似文献
19.
本文以清江流域为研究区域,基于GIS技术,对清江流域的资源环境空间要素进行分析。研究选择ArcView3.3作为软件平台,探讨了数字高程模型(DEM)的建立,在此基础上进行水文模拟分析以及地貌形态分析,提取了流域的河网,进行了流域剖面图、坡度、坡向和粗糙度图的绘制,揭示了流域内资源环境的隐含信息。总结分析结果,对区域的资源开发和环境保护的可持续性提出建议。 相似文献
20.
Mahtab Safari Shad Mahmoud Habibnejad Roshan Alireza Ildoromi 《Journal of the Indian Society of Remote Sensing》2014,42(1):107-117
Because of the difficulty of monitoring and measuring snow cover in mountainous watersheds, satellite images are used as an alternative to mapping snow cover to replace the ground operations in the watershed. Snow cover is one of the most important data in simulation snowmelt runoff. The daily snow cover maps are received from Moderate Resolution Imaging Spectroradiometer (MODIS), and are used in deriving the snow depletion curve, which is one of the input parameters of the snowmelt runoff model (SRM). Simulating Snowmelt runoff is presented using SRM model as one of the major applications of satellite images processing and extracting snow cover in the Ghara - Chay watershed. The first results of modeling process show that MODIS snow covered area product can be used for simulation and forecast of snowmelt runoff in Ghara - Chay watershed. The studies found that the SCA results were more reliable in the study area. 相似文献