AN ASSESSMENT OF LAND USE CHANGES IN FUQING COUNTY OF CHINA USING REMOTE SENSING TECHNOLOGY   总被引：8，自引：1，他引：7  

XUHan－qin 《中国地理科学(英文版)》2002,12(2):126-135

Fuqing County of southeast Chian has witnessed significant land use changes during the last decade.Re-mote sensing technology using multitemporal Landsat TM images was used to characterize land use types and to monitor land use changes in the county.Two TM scenes from 1991and 1996 were used to cover the county and a five-year time period.Digital image processing was carried out for the remotely sensed data to produce classified images.The images were further processed using GIS software to generate GIS databases so that the data could be further spatially analyzed taking the advantages of the software.Land use change areas were determined by using the change detection technique.The comparison of the two classified TM images using the above technologies reveals that during the five study years,a large area of arable lands in the county has been lost and deforestation has taken place largely because of the dramatic in-crease in built-up land and orchard.The conclusive statistical information is useful to understand the processes,causes and impacts of the land use changes in the county.The major driving force to the land use changes in the county ap-peared to be the rapid economic development.The decision makers of the county have to pay more attention to the land use changes for the county‘s sustainable development.  相似文献   

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刘序俨  洪星 《大地测量与地球动力学》2007,27(4):82-86

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应用新型辐散方程诊断“6.28”关岭大暴雨的激发和维持机制     

杜小玲  彭芳  吴古会  杨静 《高原气象》2013,32(3):728-738

利用NCEP/NCAR 1°×1°和2.5°×2.5°再分析资料、FY—2E相当黑体亮温TBB资料和区域自动站逐时降水资料,结合新型辐散方程,对2010年6月28日贵州省关岭县一次特大暴雨天气的发生和维持机制进行了诊断分析。结果表明:(1)大气运动非平衡强迫使贵州西部地区出现辐合增长,激发了该区域暴雨天气的产生;(2)能量锋生与垂直风切变的耦合强迫,促进了贵州西部地区辐合的持续增长,使暴雨得以维持;(3)对流层中低层湿位涡水平分量与垂直涡度耦合,其负值中心与地面强降水中心相对应,随后中尺度对流复合体(MCC)云团北侧出现了新生单体,第二轮暴雨随即发生并维持。  相似文献   

地球磁场的特性与分类研究   总被引：1，自引：1，他引：0       下载免费PDF全文

刘全稳 《地学前缘》2011,18(5):283-288

针对地球磁场起源研究中存在的有关地球磁极问题,在分析地球磁场特征的基础上,从地球磁场的成因和形成磁场的组合形式两方面,对地球磁场进行了分类。研究认为：地球磁场不仅具有突变性和偶极性,而且具有瞬时性、不变性等特征,初步分析了各种特性的影响原因。指出地球磁场具有二分结构,不同的分类方案可得到不同的分类结果,地球磁场可以分为...  相似文献   

滑坡与斜坡稳定性一般条分法分析中渗流作用的简化计算     

方玉树 《中国地质灾害与防治学报》2011,22(3):125-128

当滑体或潜在滑体内有倾斜的相对弱面或端部条块外侧面倾斜且有水压力作用时,采用一般条分法进行稳定性分析应比采用垂直条分法更为恰当。本文研究了对一般条分法也适用的渗流作用简化计算方法,首先给出土条渗透力的合理计算式,再根据水的面力与体力的关系给出土条周边孔隙水压力计算方法。同已有的计算方法相比,本文方法的合理性显著提高。  相似文献   

生态经济研究中的整体性视角   总被引：16，自引：15，他引：1  

徐中民  程国栋 《冰川冻土》2011,33(3):668-675

在简要介绍整体性视角含义的基础上,总结了生态经济学基本思想、主要问题、学科演替、新兴领域及未来研究主题中体现的整体性视角.分析了传统的水资源社会经济循环规律研究的劣势,在简单介绍了上升性（效率）、发展能力、恢复力和可持续性等指标及其含义后,开发了整体性视角下的水资源社会经济循环规律研究框架.最后系统地总结了整体性视角在...  相似文献   

和田河流域平原耗水驱动力与适宜绿洲规模分析   总被引：3，自引：0，他引：3  

李卫红  黎枫  陈忠升  王云  李宝明 《冰川冻土》2011,33(5):1161-1168

基于和田河流域1964—2007年的水文、气象及社会经济资料,分析了和田河流域水资源变化趋势,探讨了流域耗水量变化的驱动因素,并在此基础上运用水量平衡法和水热平衡法估算了流域适宜绿洲规模和适宜耕地面积.结果表明,1964—2007年和田河流域出山口径流呈现增幅为0.495×108m3.（10a）-1增加趋势,流域耗水量...  相似文献   

双排抗滑桩滑坡推力分配影响因素分析     

祁斌  常波  吴益平 《工程地质学报》2011,19(3):359-363

以作用形式较为简单的双排悬臂抗滑桩(未带连梁)为模型并基于结构力学位移法得出的双排桩滑坡推力传递分配计算公式为基础,结合推力较大的红石包滑坡作为工程实例,分别分析了双排桩静排距,前后排桩的截面尺寸和桩间土弹性模量对推力传递分配的影响,得出了以下结论:(1)当增大后排桩的刚度或减小前排桩的刚度时,桩土相互挤压作用越小, A2/A1随之减小,反之A2/A1增大。(2)增大排距b时,A1减小,A2在b=3~10m时逐渐减小,但是变化幅度不大; 在b=10~21m时,不断增大。(3)当增大桩间土弹性模量时,A2增大。(4)随着前排桩截面高度的增大,A1、A2逐渐增大; 随着后排桩截面高度的增大,A1、A2逐渐减小。  相似文献   

Experimental study on the performance of twin plate breakwater     

郭传胜  张宁川  李艳阳  李靖波  房卓  崔成 《中国海洋工程》2011,25(4):645-656

The wave transmission characteristics and wave induced pressures on twin plate breakwater are investigated experimentally in regular and random waves.A total of twenty pressure transducers are fixed on four surfaces of twin plate to measure the wave induced dynamic pressures.The spatial distribution of dynamic wave pressure is given along the surface of the twin plate.The uplift wave force obtained by integrating the hydrodynamic pressure along the structure is presented.Discussed are the influence of different incident wave parameters including the relative plate width B /L,relative wave height /i H a and relative submergence depth s /a on the non-dimensional dynamic wave pressures and total wave forces.From the investigation,it is found that the optimum transmission coefficient,t K occurs around B /L 0.41 ~ 0.43,and the twin plate breakwater is more effective in different water depths.The maximum of pressure ratio decreases from 1.8 to 1.1 when the relative submergence depth of top plate is increased from 0.8to +0.8.  相似文献   

Drag force on a vegetation field due to long-crested and short-crested nonlinear random waves     

Dag Myrhaug  Lars Erik Holmedal 《Coastal Engineering》2011

This paper provides a practical method for estimating the drag force on a vegetation field exposed to long-crested (2D) and short-crested (3D) nonlinear random waves. This is achieved by using a simple drag formula together with an empirical drag coefficient given by Mendez et al. (1999), in conjunction with a stochastic approach. Here the waves are assumed to be a stationary narrow-band random process. Effects of nonlinear waves are included by adopting the Forristall (2000) wave crest height distribution representing both 2D and 3D random waves.  相似文献