印尼8.7级地震前银川台形变数字化观测资料短临异常特征分析   总被引：1，自引：1，他引：1  

李国斌 《高原地震》2005,17(2):33-37

采用形变观测资料分析方法中比较常用的形态法、差分法、消除潮汐改正和零漂法，处理了银川台形变数字化观测资料，发现在印尼8．7级地震前出现了一些短临异常情况，并对异常的变化特征做了相应的分析。  相似文献   

遥测降雨抗差分析方法应用研究     

李荣容  包为民 《水文》2007,27(6):25-27,21

遥测系统观测的雨量资料常会包含粗差，根据降雨量的特征，结合抗差理论，包为民等曾提出三步抗差修正方法。将此法应用到龙颈上水库等10个水库流域的实测资料当中，验证其有效性，并分析比较各步抗差修正的效果及降雨特征与抗差效果之间的关系。结果表明，抗差修正方法可行，且第一步和第三步结合的修正效果最好；降雨中心较明确，多年降雨特征相似，强度变幅稳定的洪水，不容易出现误抗。  相似文献   

Defining the geochemical baseline: a case of Hong Kong soils     

H. B. Zhang  Y. M. Luo  M. H. Wong  Q. G. Zhao  G. L. Zhang 《Environmental Geology》2007,52(5):843-851

A geochemical baseline provides the means to distinguish between the pedogenic origin and the anthropogenic origin of the trace element in the environmental compartments. We collected 271 soil samples representative of different parent rocks and soil types from the whole territory of Hong Kong and analyzed the composition of clay mineralogy and the contents of 15 chemical elements (Fe, Cd, As, etc.) for these samples. The baseline was predicted with the method of the normalization procedure combined with the relative cumulative frequency curve. The result indicated that Fe was the best reference element for the normalization procedure among the five potential reference elements (Fe, Al, Sc, Ti, and Mn), followed by Sc and Ti. A poor correlation was found between Sc, Ti, and Cu. The predicted baseline was much lower than the A-value of the Dutch List used usually in screening the polluted soil of Hong Kong, implying that the extent of heavy metal pollution might have been underestimated with respect to local lands. We also applied the cluster analysis to distinguish the geochemical associations of the trace elements due to its importance to the baseline. Approximately three major associations including the Fe–Mn-oxides related, Al oxides or Al-bearing-clay-mineralogy related and sulfide- related associations were observed from the dendrogram.  相似文献   

An assessment of land degradation in the Save catchment of Zimbabwe     

Julia Mambo  Emma Archer 《Area》2007,39(3):380-391

The lack of reliable baseline information on land degradation is a hindrance towards its monitoring and mitigation. Of particular interest is the identification of areas susceptible to degradation. In this study, remote sensing and GIS technologies were applied to detect and map susceptibility to land degradation in Buhera district, in Save catchment, Zimbabwe. Data used included Landsat TM and ETM imagery for 1992 and 2002, agro-ecological zones, vegetation cover and population density. The study identified five preliminary categories of degradation susceptibility ranging from very high to low.  相似文献   

A non‐baseline algorithm for damage locating in flexural structures using dynamic distributed macro‐strain responses     

S. Z. Li  Z. S. Wu 《地震工程与结构动力学》2007,36(9):1109-1125

The concept of distributed strain‐sensing techniques has been proposed in our recent research, which was dedicated to utilizing the strain distributions throughout the full or partial areas of structures to detect arbitrary and unforeseen damage. An algorithm not requiring a detailed analytical model is presented for damage locating in flexural structures through the direct use of dynamic responses recorded by distributed long‐gauge strain sensors. The modal macro‐strain vector (MMSV), which has been proven to have a mapping relation with displacement mode shape, can be extracted directly from macro‐strain time‐series data, from which a damage evaluating index can be derived and used as an indicator for locating damage. Numerical examples are simulated to verify the sensitivity and effectiveness of the index in different cases. Furthermore, experimental investigations on a cantilevered beam with various long‐gauge fibre optic sensors placements are carried out to examine the feasibility and applicability of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

地形引起的雷达辐射畸变及其校正   总被引：3，自引：3，他引：3  

张永红  张继贤  林宗坚  高武俊 《测绘科学》2002,27(4):23-26

合成孔径雷达影像由于其侧视特点 ,存在着严重的地形引起的几何畸变及辐射畸变。辐射畸变不仅对 SAR辐射标定造成困难 ,而且严重影响了影像分类、土壤湿度信息提取、森林蓄积量信息提取等应用。本文将辐射畸变归结为面积效应和局部入射角效应 ,推导了散射面积归一化因子 ,以消除辐射畸变的面积效应。提出了一种以局部入射角的线性函数表达的后向散射模型 ,在此基础上 ,给出了消除局部入射角效应的校正函数。最后 ,以RADARSAT SAR影像进行地形辐射畸变校正的试验与分析  相似文献   

相位激电法(偶极-偶极)单频电磁耦合校正方法   总被引：2，自引：2，他引：2  

王书民  雷达 《物探与化探》2002,26(1):57-59,63

主要介绍一种相位激电法(偶极—偶极,以下简称偶极)电磁耦合校正方法,其原理是将视电阻率近似视为均匀大地电阻率,利用均匀大地条件下偶极装置电磁感应响应的正演计算方法,算出电磁感应响应,再将其从观测的总响应中去除,从而达到电磁耦合校正的目的。  相似文献   

重力中区地形改正系统的研制   总被引：1，自引：1，他引：1  

冯治汉 《物探与化探》2002,26(6):467-469

从传统的重力地形改正方法入手,用Delphi语言编制了Windows程序,使得多年来重力中区地形改正繁重的手工数图工作能够用计算机完成,且计算精度得到明显提高。最后用甘肃1:20万昌马幅的53个重力测点进行了试算。  相似文献   

基于GPS基准网的GPS快速静态定位及动态定位方法   总被引：3，自引：0，他引：3  

陈武  胡丛玮  陈永奇  丁晓利 《武汉大学学报(信息科学版)》2001,26(6):518-523

介绍基于GPS基准网进行GSP快速静态定位和动态定位的原理和方法。通过计算基准网改正数及其空间分布，利用内插方法求出用户站的模型误差改正数，不仅可以提高GPS整周模糊度的可靠性，而且能够大大改善GPS测量的精度。利用香港GPS基准网2001年3月的实测数据进行了解算，发现地区在该时间段内受强电离层活动的影响，采用常规GPS测量方法很难确定整周模糊度。利用传统的快速静态定位方法对香港GPS基准网其中一条边（9.2km）24h的观测数据按每15min计算，模糊度确定的准确率仅为45％。采用基准网内插改正数后，仅利用L1的观测数据模糊度确定的准确率提高到100％。点位精度平面位置由2cm提高到5mm，高程精度由4cm提高到3cm。  相似文献   

关于若干化探数据处理方法的讨论   总被引：11，自引：3，他引：11  

纪宏金  林瑞庆等 《地质与勘探》2001,37(4):56-59

化探数据处理中的系统误差校正和异常识别方法很多，移动标准化法、分区标准化法和衬度系数法是其中的几种方法，主要对这几种方法做了简单的介绍并对其效果进行了对比，最后着重讨论了C型变换法的优点。  相似文献