Spatial and temporal variability of pore‐water pressures in residual soil slopes in a tropical climate     

R. B. Rezaur  H. Rahardjo  E. C. Leong 《地球表面变化过程与地形》2002,27(3):317-338

It is critical to understand and quantify the temporal and spatial variability in hillslope hydrological data in order to advance hillslope hydrological studies, evaluate distributed parameter hydrological models, analyse variability in hydrological response of slopes and design efficient field data sampling networks. The spatial and temporal variability of field‐measured pore‐water pressures in three residual soil slopes in Singapore was investigated using geostatistical methods. Parameters of the semivariograms, namely the range, sill and nugget effect, revealed interesting insights into the spatial structure of the temporal situation of pore‐water pressures in the slopes. While informative, mean estimates have been shown to be inadequate for modelling purposes, indicator semivariograms together with mean prediction by kriging provide a better form of model input. Results also indicate that significant temporal and spatial variability in pore‐water pressures exists in the slope profile and thereby induces variability in hydrological response of the slope. Spatial and temporal variability in pore‐water pressure decreases with increasing soil depth. The variability decreases during wet conditions as the slope approaches near saturation and the variability increases with high matric suction development following rainfall periods. Variability in pore‐water pressures is greatest at shallow depths and near the slope crest and is strongly influenced by the combined action of microclimate, vegetation and soil properties. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

A DYNAMIC MODE FOR RELATIONSHIP BETWEEN FLOOD/DROUGHT IN YANGTZE RIVER VALLEY AND LOW FREQUENCY WAVE ORIGINATED FROM TROPICAL SEA AREA     

MIAO Qiuju  XU Xiangde  YAO Wenqing  ZHANG Xuejin 《Acta Meteorologica Sinica》2002,16(3):272-281

According to statistic analysis on sea surface temperature(SST)anomaly features in theNorth Pacific in winters and springs prior to the summer flood/drought in the middle and lowerreaches of the Yangtze River(hereafter referred to as MLRY),a strong signal SST key area thataffects local flood/drought is put forward,that is the equatorial eastern Pacific.The response ofgeneral circulation in the Northern Hemisphere to SST anomaly in the key area is furtherinvestigated. The low frequency wave train structure of correlation between the eastern PacificSST and the height at 500 hPa in the Northern Hemisphere is also studied,which reflects thedynamic features of teleresponse of local flood/drought at extratropics to tropical SST anomaly.Through introducing SST anomaly in the strong signal area in numerical experiments,the flood inYangtze River Valley is successfully simulated and the similar wave train pattern in the flow field isobtained too.Altogether,the physical picture and dynamic mode of the flood in the Yangtze RiverValley are described in this work.  相似文献   

长江巨洪前期物理因子的配置   总被引：4，自引：4，他引：4  

冯利华 《地理科学》2002,22(4):504-507

提出了长江巨洪前期物理因子配置的概念，在每一次巨洪发生之前，影响巨洪的主要物理因子之间一般都会表现出相似的特征，即出现一些固有的配置，这些配置正是长江发生巨洪的强信号，对长江巨洪的预测研究具有重要的指示作用。  相似文献   

洪水演进三维模拟仿真系统可视化研究   总被引：14，自引：0，他引：14  

袁艳斌  袁晓辉  张勇传  刘吉平  侯国祥 《山地学报》2002,20(1):103-107

洪水演进仿真系统的研制，是实施“数字流域”工程的重要组成部分；结合洪水演进可视化目标的分析，基于Visual C 系统开发平台，融GIS技术和Opengl开发技术，采用三角形逼近、光滑处理和加入法向量以控制光照的方式，实现了流域地形及河床的三维可视化仿真；应用广度优先搜索算法确定了运动水体与流域河床形态的自适应与自相依的关系，使流域洪水演进模拟具有真实自然的可视化效果。所研制的系统雏形，可有效的模拟流域洪水的三维演进过程；  相似文献   

云南省防洪空间信息系统构建   总被引：4，自引：1，他引：4  

朱静  师玉娥  周斌  周运龙  张杰  范宏忠 《云南地理环境研究》2003,15(2):19-26

通过讨论应用地理信息系统（GIS）技术，立足现实对相关空间数据进行集成和整合处理，实现防洪空间信息的数字化、标准化，为优化防汛指挥工作手段提供基础。系统数据库饭知不同比例尺精度的空间基础数据以满足不同目的的需求，对相关水文、防洪设施、全省洪涝风险和重点区风险图、土地利用等图件进行系统整合。系统有较强的管理功能和分析功能，可提高云南省防洪空间信息的共享度和系统有效管理，为政府统一组织和指挥抗洪救灾提供重要的辅助决策支持手段。  相似文献   

Sectoral Shifts and Occupational Migration in the United States     

Mark E. Reisinger 《The Professional geographer》2003,55(3):383-395

This research is grounded in notions of differential economic restructuring across employment sectors and geographic space, as well as migration selectivity by occupation. A series of unconstrained competing‐destinations models were employed to analyze the response by workers in thirteen occupational categories to sectoral employment change, average wages, and distance. As was hypothesized, workers in occupations that require high levels of education and skills are more responsive, in terms of migration, to economic opportunities in alternative labor‐market areas. However, the results do not support the hypothesis that highly educated and skilled workers migrate longer distances. Further investigation suggests that opportunities for highly educated and skilled workers may be clustering in relatively few areas that are in relatively close proximity.  相似文献   

对中国防洪减灾问题的基本认识和建立具有中国特色的防洪减灾体系的初步设想   总被引：9，自引：0，他引：9  

徐乾清 《水文》2003,23(2):1-7

阐述了防洪成灾的基本认识及防洪减灾对策的发展过程，分析了中国洪水灾害分布的特征和防洪减灾基本对策的要求，探讨了建立具有中国特色的防洪成灾体系，提出了当前防洪成灾研究规划中出现的若干问题。  相似文献   

上海市防汛辅助决策系统研究   总被引：4，自引：0，他引：4  

郑晓阳  胡传廉 《水文》2003,23(2):33-36

针对威胁上海的三大水灾，研制暴雨积水模型、风暴潮模型、河网水力模型、灾害评估模型，在GIS基础上建立了上海市防汛辅助决策系统，实现了对处于平原感潮河网的上海市洪涝灾害的实时监测、分析预报、风险评估和网上发布。为分析洪涝形势、制定防汛成灾方案、进行灾情评估以及工程管理，提供准确、及时、全面的信息支持。阐述了系统的总体设计、功能模块、关键技术和特色，分析了GIS、水动力学模型在系统中的作用。  相似文献   

吉林省水旱灾害规律分析   总被引：1，自引：0，他引：1  

王子臣 《水文》2003,23(6):18-20,27

水旱灾害在自然灾害中占有重大比重，对人类危害极大，正确认识水旱灾害发生的规律与特点，对防治与减轻自然灾害有着重要作用。对吉林省水旱灾害的危害及其发生规律和特点进行了分析。  相似文献   

洪水对非防洪工程建设项目影响评价方法研究          下载免费PDF全文

陆桂华  陆宝宏  张行南  宋兰兰 《水科学进展》2003,14(4):480-484

讨论了洪水对洪泛区或滞蓄洪区中非防洪工程建设项目影响评价方法,包括洪灾直接经济损失和间接经济损失的估算方法,洪灾发生时含有有毒物质的非防洪工程建设项目对环境的影响,以及对地下水的污染等影响评价方法.这些方法是洪水对非防洪工程建设项目影响评价的核心,也是整个影响评价的重点和难点所在.这些方法可为制定洪水对洪泛区非防洪工程建设项目影响评价指南或规范提供科学依据.  相似文献