Homogenization of Climate Data: Review and New Perspectives Using Geostatistics

The homogenization of climate data is of major importance because non-climatic factors make data unrepresentative of the actual climate variation, and thus the conclusions of climatic and hydrological studies are potentially biased. A great deal of effort has been made in the last two decades to develop procedures to identify and remove non-climatic inhomogeneities. This paper reviews the characteristics of several widely used procedures and discusses the potential advantages of geostatistical techniques. In a case study, the geostatistical simulation approach is applied to precipitation data from 66 monitoring stations located in the southern region of Portugal (1980–2001). The results from this procedure are then compared with those from three well established statistical tests: the Standard normal homogeneity test (SNHT) for a single break, the Buishand range test, and the Pettit test. Promising results from the case study open new research perspectives on the homogenization of climate time series.     

测绘资料档案信息一站式管理平台关键技术

在对现有测绘资料管理方法进行研究的基础上,依据信息化测绘的要求,设计了测绘资料档案信息一站式管理方案,实现了测绘资料档案信息一站式管理平台。实践证明,该方案能够适应不同部门的测绘资料管理需求,在提高资料管理效率的同时能够为用户提供更为便捷的测绘资料服务。     

基于小波方法的平滑算法在引力透镜中的应用

基于离散小波变换(DWT)方法,提出了一种可用于计算三维数值模拟样本面密度的平滑算法.为检验方法的有效性,利用该算法研究了两组不同质量解析度的引力透镜数值模拟样本,样本采用了暗物质晕的等温椭球模型,使用蒙特卡罗方法生成.计算结果表明此算法能够在很高的精度上构建引力透镜模拟样本的面密度分布轮廓,由面密度计算出来的透镜的临界曲线和焦散曲线也能较好地和理论曲线吻合,结果是令人满意的.同时比较了三组不同的小波基的计算结果,包括Daub4,Daub6和B-spline 3th,给出了最优的选择.在不损失平滑效果的同时,此算法具有非常高的速度,非常适合于处理以后更高精度的N体数值模拟.     

H layering in the top meter of Mars

We explore the capability of a method of mapping the depth distribution of a hydrogen-rich layer in the top meter of Mars from the neutron currents measured by the Mars Odyssey Neutron Spectrometer. Assuming the soil can be modeled by two layers of known composition having different hydrogen contents, simulations allow an inversion of the neutron data into knowledge of depth and hydrogen content of the lower layer. The determination of these variables is sensitive to the hypothesis of chemical composition of the soil. We quantify this contribution to the uncertainty in the method first in terms of individual chemical elements and then in terms of macroscopic absorption cross sections. To minimize this source of error, an average composition was inferred from Mars Exploration Rover data. Possible compositions having a wide range of macroscopic absorption cross sections were used to evaluate the uncertainty associated with our calculations. We finally compare our results to ice table depth estimates predicted by two published theoretical models at locations where the composition is relatively well known. The fit is excellent in the southern high latitudes but questionable in the northern high latitudes. Possible explanations of these differences include the high geographical variations of the neutron currents relative to the spatial width of the response function of the instrument and the overly simple model we, of necessity, used for surface layering.     

地理编码原理及其本地化解决方案

地理编码技术具有广阔的发展前景,使用它可以利用记录的属性数据直接定位出其地理坐标。完整阐述了地理编码的技术核心及实现方式,并对实现其本地化的关键技术-数据标准化提出了解决方案。在文章的最后阐述了相关的结论。     

A new 3D laser-scanning and GPS combined measurement system

Terrestrial laser scanning (TLS) is widely used because of its ability to quickly acquire high-density and high-precision 3D image and topographic data. However, it can only acquire independent coordinate system points, which restricts its application in large-scale deformation monitoring. In this study, we constructed a measurement system to acquire global coordinate point cloud data by combining TLS and GPS (Global Positioning System). The coordinate values of retro-reflective targets could be acquired in different coordinate systems, the GPS coordinate and the TLS station coordinate, synchronously. Our experiments showed that, after registration with the homonymy points acquired by 30-min short-baseline differential GPS using the ICP algorithm, the positional accuracy of the TLS retro-reflective target center in the global coordinate was better than 10 mm. This high precision meets, for instance, the requirements of coal mining subsidence monitoring. We used our new combined measurement system to acquire and process the point cloud data of a frame structure. The measurements demonstrated the practicability and robustness of the new measurement system.     

武山台数据信息管理系统设计与实现

根据武山水化学综合地震台的具体情况，在微机汉字ＤＯＳ环境下利用ＦｏｘＢＡＳＥ＋２．１０关系型数据库成功开发了武山台数据信息管理系统。本系统全部采用Ｆｏｘｂａｓｅ＋数据库编写，主要用于地震台站的数据管理及各种报表的自动生成。程序采用自项向下，逐步求精方法设计，全部功能模块均采用下拉式窗口。程序设计中，最大限度地采用了容错处理。一年多的实际运行表明，系统操作简单，界面友好，容错功能完善，完全满足台站日常工作需要。     

电磁波层析成像数据采集系统

阐述了电磁波透射层析成像数据采集系统的研制，对软硬件的设计作了较详细的说明，还介绍了相应的技术细节。该系统是一个软件、硬件结合的单片机控制数据采集系统：硬件全部采用低功耗、高速器件、其中Ａ／Ｄ转换器采１２位双各分型模数据转器。     

KCPIS的空间数据模型与用户界面

本文介绍了全国重点建设项目信息系统的空间数据模型，以用户为中心的可视化界面和专用查询、统计、制图功能。     

利用单张航空像片和DEM实现GIS空间数据的更新

利用遥感信息获取空间地理数据是ＧＩＳ与ＲＳ技术集成应用研究的重要方面。运用数字地形数据和共线方程，对扫描数字化的单张调绘航片进行数字纠正，从而更新ＧＩＳ空间数据库的方法，是一种可供选择且很有吸引力的空间源数据获取方法。本文介绍的系统可在没有摄影测量设备的情况下运行，所需的硬件设备并不昂贵．其特点和精度均能较好地适用于大比例尺ＧＩＳ的应用。