灌淤土壤可溶性盐分空间变异性与棉花生长关系研究   总被引：8，自引：3，他引：8  

杨玉玲  田长彦  盛建东  文启凯 《干旱区地理》2002,25(4):329-335

运用地统计学方法，在灌淤土壤上进行了棉田土壤可溶性盐分的空间变异规律与棉花生长关系系统研究。传统统计学分析表明土壤盐分测试数据基本符合正态分布；在一定取样间距下，土壤可溶性盐分的田间合理取样数目为27。半方差分析显示：土壤可溶性盐分具中等的水平变异性，但随着聚样深度的增加未表现出明显的垂直变异特性；随着棉花的生长发育，土壤可溶性盐分呈现出逐渐减弱的时间变异规律，采用直线或曲线拟合方程估计了可溶性盐分的半方差图及其参数，并绘制了其相应的等值线图。土壤可溶性盐分与棉花产量之间的相关分析表明：可溶性盐分含量与棉花产量之间呈显著负相关关系，且花铃期的相关性较播前显著。研究结果为提高田间试验有效性以及盐渍化土壤改良提供了科学依据与基础资料。  相似文献   

Combining ordination techniques and geostatistics to determine the patterns of diatom distributions at Lake Lama, Central Siberia   总被引：4，自引：0，他引：4  

Ulrike Kienel  Thomas Kumke 《Journal of Paleolimnology》2002,28(2):181-194

The patterns of spatial variation of diatom assemblages from surface sediments in Lake Lama were quantified using a combined approach of ordination and geostatistics. The aims were (i) to estimate the amount of variation between diatom assemblages within the lake, (ii) to model the spatial variability of the diatom assemblages and their diversity, and (iii) to map the diatom distributions in the lake. A correspondence analysis (CA) separated the diatom assemblages into a planktonic and a periphytic group. Rheophilic taxa were found within the periphytic group. Variogram analysis showed that only the sample scores of the first CA axis and the Shannon diversity index were spatially structured. The range of spatial correlation was estimated to be 55 km for both variables. The diversity and, to a lesser extent, the sample scores had considerable small-scale variability of about 20 and 3%, respectively. Estimates of the first component of the CA and the Shannon index were derived using block-kriging. The maps of the estimates provided a basis for partitioning Lake Lama according to the spatial structures into an eastern and a western basin, a north–south connection between the basins, and a north–south directed tip at the far eastern end. It was shown that variation in diatom assemblages is mainly spatially structured at the catchment scale and that there is a considerable amount of variation at smaller scales. According to the modeled spatial distribution, the assemblages are most likely affected by the lake size, morphology, and the water and nutrient input introduced by rivers. This has to be taken into account when paleolimnological interpretations are drawn from records of complex lake systems like Lake Lama.  相似文献   

On the spatial relationship between landslides and causative factors on Lantau Island, Hong Kong   总被引：8，自引：0，他引：8  

C. H. Zhou  C. F. Lee  J. Li  Z. W. Xu 《Geomorphology》2002,43(3-4)

This paper presents a statistical approach to study the spatial relationship between landslides and their causative factors at the regional level. The approach is based on digital databases, and incorporates such methods as statistics, spatial pattern analysis, and interactive mapping. Firstly, the authors propose an object-oriented conceptual model for describing a landslide event, and a combined database of landslides and environmental factors is constructed by integrating the various databases within such a conceptual framework. The statistical histogram, spatial overlay, and dynamic mapping methods are linked together to interactively evaluate the spatial pattern of the relationship between landslides and their causative factors. A case study of an extreme event in 1993 on Lantau Island indicates that rainfall intensity and the migration of the center of the rainstorm greatly influence the occurrence of landslides on Lantau Island. A regional difference in the relationship between landslides and topography is identified. Most of the landslides in the middle and western parts of the island occurred on slopes with slope angles of 25–35°, while in the eastern part, the corresponding range is 30–35°. Overlaying landslide data with land cover reveals that a large number of landslides occurred in the bareland and shrub-covered area, and in the transition zones between different vegetation types. The proposed approach can be used not only to analyze the general characteristics of such a relationship, but also to depict its spatial distribution and variation, thereby providing a sound basis for regional landslide prediction.  相似文献   

基于网格的空间信息模型与服务技术研究   总被引：12，自引：0，他引：12  

何小朝  李琦  承继成 《地理与地理信息科学》2003,19(4):60-63

空间信息基础设施是实现数字城市的核心与基础，现有的万维网已经不能满足空间信息访问与处理的需要。该文对以空间信息为核心和基础的数据网格——空间信息网格的基础理论及网格中的空间信息模型与服务技术：进行研究。提出了空间信息网格的若干关键技术及网格中的空间信息模型的特点与要求，并对空间信息网格服务进行了初步的探讨。  相似文献   

西藏冈底斯东段成矿系列区域地球化学预测   总被引：4，自引：5，他引：4       下载免费PDF全文

孙忠军  任天祥向运川 《中国地质》2003,30(1):105-112

西藏冈底斯乐段优势矿床成矿系列预测是当前需要解决的重要问题。文中研究了成矿系列矿源场特征，以及地球化学靶区与矿床成矿系列的联系，揭示了矿化规模的地球化学控制因素，计算了因素耦合系数。预测冈底斯构造带是4种类型矿床成矿系列的密集区。  相似文献   

Scaling effects on modeled surface energy-balance components using the NOAH-OSU land surface model   总被引：3，自引：0，他引：3  

V. Sridhar  Ronald L. Elliott  Fei Chen 《Journal of Hydrology》2003,280(1-4):105-123

As surface exchange processes are highly non-linear and heterogeneous in space and time, it is important to know the appropriate scale for the reasonable prediction of these exchange processes. For example, the explicit representation of surface variability has been vital in predicting mesoscale weather events such as late-afternoon thunderstorms initiated by latent heat exchanges in mid-latitude regions of the continental United States. This study was undertaken to examine the effects of different spatial scales of input data on modeled fluxes, so as to better understand the resolution needed for accurate modeling. A statistical procedure was followed to select two cells from the Southern Great Plains 1997 hydrology experiment region, each 20 km×20 km, representing the most homogeneous and the most heterogeneous surface conditions (based on soil and vegetation) within the study region. The NOAH-OSU (Oregon State University) Land Surface Model (LSM) was employed to estimate surface energy fluxes. Three scales of study (200 m, 2 and 20 km) were considered in order to investigate the impacts of the aggregation of input data, especially soil and vegetation inputs, on the model output. Model results of net radiation and latent, sensible and ground heat fluxes were compared for the three scales. For the heterogeneous area, the model output at the 20-km resolution showed some differences when compared with the 200-m and 2-km resolutions. This was more pronounced in latent heat (12% decrease), sensible heat (22% increase), and ground heat flux (44% increase) estimation than in net radiation. The scaling effects were much less for the relatively homogeneous land area with 5% increase in sensible heat and 4% decrease in ground heat flux estimation. All of the model outputs for the 2- and 20-km resolutions were in close agreement. The results suggested that, for this study region, soils and vegetation input resolution of about 2 km should be chosen for realistic modeling of surface exchange processes. This resolution was sufficient to capture the effects of sub-grid scale heterogeneity, while avoiding the data and computational difficulties associated with higher spatial resolutions.  相似文献   

基于约束点的曲线一致性化简   总被引：5，自引：0，他引：5  

应申  李霖 《武汉大学学报(信息科学版)》2003,28(4):488-491

详细探讨了基于平面上的特征约束点(无论在曲线上还是在曲线外)的曲线化简，并针对各种情况提出了一致性化简的方法。  相似文献   

Creating a GIS application for retail centers in Jeddah city   总被引：2，自引：0，他引：2  

AbdulKader A. Murad   《International Journal of Applied Earth Observation and Geoinformation》2003,4(4):329-338

The aim of this paper is to identify the role of geographical information systems (GIS) in supporting retail planners in monitoring and analyzing retail development and growth. At first, a review about retail planning and its relevant issues is made. Second, GIS is defined together with its applications in retail planning. The third part discusses the created GIS application that is designed for two retail centers in Jeddah city, Saudi Arabia. This application is created to help planners in defining the distribution of retail demand, describing customers profile, analyzing trade areas and modeling retail flows. Two useful models have been produced by this study. One is called market penetration and the other is based on spatial interaction technique. The former is created to examine retail center catchment area, while the latter is used to model the interaction between demand areas and retail centers.  相似文献   

解析计算法与吴尔夫网投影法求解震源机制结果比较     

张萍  蒋秀琴  高艳玲  谷光裕  吴野 《地震》2003,23(4):43-48

利用“基于GIS地震分析预报系统”提供的用地震初动符号求震源机制解软件，获得了1999年11月辽宁岫岩—海城交界地区20个ML≥4．0地震的震源机制解．并将求解结果与采用吴尔夫网投影法得到的震源机制结果进行比较。结果表明．二种求解震源机制得到的节面(A、B)、力轴(P、T)比较接近，对应效果比较好。  相似文献   

青藏高原气温分布的空间插值方法比较   总被引：66，自引：9，他引：66  

李新  程国栋  卢玲 《高原气象》2003,22(6):565-573

使用反距离平方、趋势面、Kriging插值、Cokriging插值和综合方法对青藏高原1961-1990年30年平均1月气温进行空间插值比较研究，其中后两种方法能够把影响青藏高原气温分布的关键因素——高程置于插值算法之中。反距离平方和趋势面插值的结果都与实际情况相差较远；普通Kriging插值能够反映出青藏高原气温分布的一定的空间结构，但结果依然不好；由于考虑了高度变量，Cokriging插值表现出一定程度的性能改进，但因为台站海拔高度偏低，插值结果依然不理想。前4种方法效果不好的原因主要是因为青藏高原上气象台站稀少且高原西北地区无气象台站。综合方法把气温分解为结构化分量和随机分量，使用直减率把气温订正到同一海拔高度后，再对它们做Kriging插值分析，其结果较为正确地反映了青藏高原气温空间分布的特征，误差远小于其它方法。研究结果表明：样本本身的空间分布是影响插值精度的重要因素，合理的采样设计是必要的前提；对于台站稀少的地区，必须把随机插值方法和确定性方法结合起来估计气候变量的空间分布。同时给出了青藏高原1月的气温空间分布状况。  相似文献