AN INSIGHT ON DRIVERS OF LAND USE CHANGE AT REGIONAL SCALE   总被引：2，自引：0，他引：2  

SHAO Jing-an WEI Chao-fu XIE De-ti 《中国地理科学(英文版)》2006,16(2):176-182

1INTRODUCTION Land use change (LUC) involves both changes to a dif- ferent function and shifts in intensity within a function. Today, researches on LUC are aiming at regional scale, andthestudiesofthetypicalregionalLUC drivingforces at meso- and small-scale become a key issue (VAN DIGGELEN et al., 2005; CHAPLOT et al., 2005). The studies of regional LUC driving forces are to reveal the realmotivationbehindtheLUCanditsinteractingmech- anism, so as to simulate and predict the p…  相似文献   

Prediction of hydrodynamic forces on submarine pipelines using an improved Wake II Model     

Iwan R. Soedigdo  K.F. Lambrakos  Billy L. Edge 《Ocean Engineering》1998,26(5):431-462

The hydrodynamic force model for prediction of forces on submarine pipelines as described includes flow history effect (wake effects) and time dependence in the force coefficients. The wake velocity correction is derived by using a closed-form solution to the linearized Navier–Stokes equations for oscillatory flow. This is achieved by assuming that the eddy viscosity in the wake is only time dependent and of a harmonic sinusoidal form. The forces predicted by the new Wake (Wake II) Model have been compared to Exxon Production Research Company Wake Model in terms of time histories (force shape) and magnitudes of peak forces. Overall, the model predictions by the Wake II Model are satisfactory and represent a substantial improvement over the predictions of the conventional models. The conventional force models representing adaptations of Morison's equation with ambient velocity and constant coefficients give predictions that are in poor agreement with the measurements especially for the lift force component. The Wake II Force Model can be used for submarine pipeline on-bottom stability design calculations for regular waves with various pipe diameters.  相似文献   

Spatial heterogeneity of the driving forces of cropland change in China   总被引：9，自引：2，他引：7  

LIU Xuhua    WANG Jinfeng  LIU Mingliang  & MENG Bin    . Institute of Geographic Sciences  Natural Resources Research  Chinese Academy of Sciences  Beijing  China  . Graduate School of the Chinese Academy of Sciences  Beijing  China  . College of Arts  Sciences of Beijing Union University  Beijing  China  . School of Forestry  Wildlife Sciences  Auburn University  Auburn  Alabama  AL  USA 《中国科学D辑(英文版)》2005,48(12):2231-2240

Along with the increasing problems of rapid popu-lation increase, resources scarcity and environment deterioration, the interaction between human devel-opment and natural environment changes, especially the Land-Use/Land-Cover, LUCC issue is becoming a frontier and hot field[1], in which investigation on the mechanisms of land use change is one of the three core issues. Deficient natural resources, in particular the shortage of cropland resource in China, are the important constraints to Ch…  相似文献   

甘肃民勤荒漠区植被演替特征及驱动力研究--以民勤为例   总被引：43，自引：20，他引：23  

彭鸿嘉  傅伯杰  陈利顶  杨自辉 《中国沙漠》2004,24(5):628-633

通过对40多年来民勤荒漠植被类型、植被演替特征的分析,发现民勤荒漠区的自然植被类型20世纪50年代大体可分为5个植被型,19个群系,现在只有9个群系;民勤土地旱化现象日趋严重,脆弱的生态系统进行着逆向演替,群落的生物多样性及植被类型减少,生态系统的稳定性减弱且结构趋于简单、功能衰退,荒漠植被进一步取代了草甸植被成为优势种。生态位变宽;同时,通过对地下水位、降水量、植被盖度近20a的定位观测,定量研究植被退化的驱动因子表明：人类的各种经济活动导致地表径流的大幅度减少、超采地下水,使地下水位急剧下降,成为植被退化最直接的根源。  相似文献   

河南省建设用地扩张及其驱动力分析   总被引：1，自引：0，他引：1  

吕可文  苗长虹  安乾 《地理与地理信息科学》2012,28(4):69-74

通过对1996—2008年河南省建设用地扩张及驱动力分析,得出以下结论:1)河南省建设用地扩张十分迅速,尤其是随着中原崛起、中原城市群战略的提出及逐步实施,建设用地扩张速度更快,并且城镇用地、独立工矿用地和交通用地的增加是其重要原因;2)建设用地结构的信息熵指数逐渐增大,土地职能类型逐渐多样化,土地利用结构趋于均衡,并且建设用地的效益也在不断提高;3)建设用地扩张与经济增长、工业化、人口增长、城镇化以及由此而引发的基建需求具有很强的相关性;4)与全国和其他区域相比,驱动河南省建设用地扩张的主要力量具有特殊性,快速城镇化进程以及经济社会发展引发的基础设施需求是建设用地扩张的主要驱动力,而经济增长、人口增长及工业化是建设用地扩张的一般驱动力;5)经济发展水平高和城镇化进程快的中原城市群地区,特别是郑州、洛阳、新乡、焦作等地市是建设用地扩张的主要空间。  相似文献   

Monitoring directions and rates of change in trees outside forests through multitemporal analysis of map sequences   总被引：1，自引：0，他引：1  

Tobias Plieninger 《Applied geography (Sevenoaks, England)》2012,32(2):566-576

This study explores the potential of historical maps to detect, measure and monitor changes of trees outside forests. The main goal is to assess local-level changes of scattered trees and orchards and their land-use determinants in two areas in Southern Germany between 1901/1905 and 2009. Firstly, overall landscape changes are recorded. Secondly, the spatial-temporal trajectories of scattered trees and their land-use determinants are identified. Thirdly, changes in quantity and fragmentation patterns of traditional orchards are analyzed in their relationship to overall land-cover change. The results confirm major losses in scattered trees, mainly due to urbanization, agricultural intensification, and land abandonment. They further reveal that, while orchards have persisted in total area, they have undergone critical changes toward a simplified landscape structure and loss of the traditional land-use mosaic, which is a characterizing feature of high nature value landscapes. Multi-temporal assessment showed that most trends have been continuous and did not change directions over time, but rather accelerated during periods of rapid change (most dramatically in the 1950-1990 period). The case of orchards and scattered trees illustrates a major problem of cultural landscapes in Europe: Semi-natural landscape features of high nature value are threatened by both intensification and abandonment of land uses. This makes their conservation a potentially costly enterprise, as both opportunity costs for lost alternative land uses and for conservation management costs arise.  相似文献   

An interdisciplinary approach to depict landscape change drivers: A case study of the Ticuiz agrarian community in Michoacan, Mexico   总被引：1，自引：0，他引：1  

Minerva Campos  Alejandro Velázquez  Ángel Guadalupe Priego-Santander 《Applied geography (Sevenoaks, England)》2012,32(2):409-419

Landscape changes are driven by a combination of physical, ecological and socio-cultural factors. Hence, a large amount of information is necessary to monitor these changes and to develop effective strategies for management and conservation. For this, novel strategies for combining social and environmental data need to be developed. The purpose of this study is to demonstrate the value of an innovative interdisciplinary approach to help in explaining landscape change. We integrated three main sources of information: biophysical landscape attributes, land-use/cover change analysis and social perceptions of land-use change, institutional and policy factors and environmental services. Multivariate statistical analysis was used to develop a weight for each variable described or quantified. Finally we identified proximate causes and underlying driving forces of land transformation in the study area. The study was undertaken in a typical community in Mexico.  相似文献   

不同职能城市土地利用结构影响因素分析   总被引：2，自引：0，他引：2  

鲁春阳  高成全  杨庆媛  文枫 《地域研究与开发》2012,31(1):120-125

根据2007年地级以上城市的土地和社会经济数据,采用主成分、聚类分析、相关分析等方法,分析不同职能城市土地利用结构特征及影响因素。结果表明:(1)根据城市职能主因子得分,结合城市规划及发展实际,将地级以上规模城市分为区域综合性城市、第二产业城市、交通城市、文化旅游城市、地方中心城市5类。(2)不同职能城市土地利用结构信息熵以中等水平为主,土地利用类型多样性提升空间较大。(3)经济因素、产业结构、基础设施和城市人口等是影响土地利用结构的主要因素,但对不同职能城市用地结构的影响次序和影响程度异质性明显。  相似文献   

奥运短时临近预报实时数据处理   总被引：6，自引：1，他引：5  

王玉彬  周海光  余东昌  周勇  苏德斌  梁丰 《气象》2008,34(7):75-82

详细分析了目前短时临近预报系统对自动气象站数据质量控制、探测数据更新频率、组网雷达时间同步观测与基数据实时传输、探测数据的实时传输技术、基于目录监控的数据监控与分发机制、基于开源的软件开发、数据格式等方面的需求.在此基础上,建立了北京奥运短时临近预报数据快速收集处理系统并已经投入业务运行,该系统实现了探测数据的实时传输、组网雷达时间同步观测和基数据实时传输、基于消息驱动的数据实时监控和分发、探测数据格式规范化等功能,基本满足北京2008年奥运短时临近预报系统的数据预处理业务需求.  相似文献   

红外焦平面探测器信息获取与预处理电路设计     

范文龙  董峰  傅雨田 《遥感学报》2014,18(Z1):30-34

针对中国科学院上海技术物理研究所研制的1500元红外线列焦平面探测器的输出特性,提出了以低噪声运放为核心的信息获取电路和以FPGA(Field Programmable Gate Array)为核心的数据预处理的设计方案,实现了驱动电路和探测器的良好匹配,较好地发挥了探测器高灵敏度的特性.测试结果表明,该方案不仅对系统获得优于50 mK噪声等效温差的高灵敏度成像起到了重要作用,足够宽的量化设计还保证了系统的动态范围和图像的丰富层次.该设计方案已成功应用在一些其他类型的红外焦平面探测器中.  相似文献