从洛杉矶地区地震实验计划说起   总被引：3，自引：1，他引：3  

张先康 《国际地震动态》2003,(12):8-10

简要介绍了美国洛杉矶地震实验计划(LARSE)的研究目的、科学思路以及一些重要的研究成果。受LARSE计划实践的启发，文章对我国即将开展的城市活断层探测研究思路提出了几点科学认识：①进行深浅活动构造相结合的探测，建立直到震源深度的活动断裂立体图像；②实施折射／反射相结合的综合性探测，发展高分辨折射技术，弥补数百米-数千米深度范围成像的不足；③重要的活动断层常常具有一定的规模，在空间上构成复杂的构造格局，因此，活断层探测不能局限在城市，而应在一定的空间范围中进行。  相似文献   

Use of Geomorphological Information in Indirect Landslide Susceptibility Assessment   总被引：31，自引：6，他引：31  

van Westen  C. J.  Rengers  N.  Soeters  R. 《Natural Hazards》2003,30(3):399-419

The objective of this paper is to evaluate the importance of geomorphological expert knowledge in the generation of landslide susceptibility maps, using GIS supported indirect bivariate statistical analysis. For a test area in the Alpago region in Italy a dataset was generated at scale 1:5,000. Detailed geomorphological maps were generated, with legends at different levels of complexity. Other factor maps, that were considered relevant for the assessment of landslide susceptibility, were also collected, such as lithology, structural geology, surficial materials, slope classes, land use, distance from streams, roads and houses. The weights of evidence method was used to generate statistically derived weights for all classes of the factor maps. On the basis of these weights, the most relevant maps were selected for the combination into landslide susceptibility maps. Six different combinations of factor maps were evaluated, with varying geomorphological input. Success rates were used to classify the weight maps into three qualitative landslide susceptibility classes. The resulting six maps were compared with a direct susceptibility map, which was made by direct assignment of susceptibility classes in the field. The analysis indicated that the use of detailed geomorphological information in the bivariate statistical analysis raised the overall accuracy of the final susceptibility map considerably. However, even with the use of a detailed geomorphological factor map, the difference with the separately prepared direct susceptibility map is still significant, due to the generalisations that are inherent to the bivariate statistical analysis technique.  相似文献   

Application of Weights of Evidence to Mineral Potential Mapping of Yujiacun Ore Field in Northwest Yunnan Province, China   总被引：1，自引：0，他引：1  

ZHAO　Pengda 《中国地质大学学报(英文版)》2003,14(3):269-273

The multivariate information conprehensive processing technique is especially important at present to the digital mineral prospecting. However, the GIS-based weights of evidence have provided us with powerful tool for the quantitative assessment of mineral resource potential. In this paper, the mineralization model is established, based on the achievements made by previous researchers, to mend such deficiencies ad few references on ore fields in Yujiacun, Yunnan Province and the shortage of quantitative prediction and assessment of mineral resources. In addition, the weights of evidence are used to make a systematic quantitative prediction and assessment of mineral resources there, so that 2 mineral prospecting target areas of grade Ⅰ and 8 mineral prospecting target areas of grade Ⅱ are delineated, providing the further mineral resource exploration with the basis for the selection of mineral deposits.  相似文献   

悬吊式钢混结构体系抗震试验与分析     

罗英  吴敏哲  邓景纹  项仕权 《世界地震工程》2004,20(2):134-138

悬吊式钢混结构体系是一种新型结构体系，通过一榀1／2比例此种框架的拟静力试验，研究了这种结构在低周反复水平荷载作用下的受力特点、变形和耗能能力以及破坏机理等，试验表明此种框架与传统异形柱框架的性能不同，为此种结构体系的应用提供了试验基础。  相似文献   

国内外PMP/PMF的发展和实践   总被引：8，自引：3，他引：8  

王国安 《水文》2004,24(5):5-9,47

对20世纪80年代以来PMP／PMF在国内外的发展和实践情况作了简要的介绍和评论。内容包括PMP／PMF定义、估算方法、成果合理性检查和概率。PMP估算方法包括概化估算法、当地暴雨放大、暴雨移置、暴雨组合、推理模式和统计估算法。PMF估算着重介绍了由PMP转化为PMF的产流和汇流特点，以及目前在南非和法语非洲国家广泛应用的经验公式。  相似文献   

变形监测基准点的稳定性检验   总被引：1，自引：0，他引：1  

詹龙喜  唐继民  汪维春  周金龙 《上海国土资源》2004,(2):34-36,43

基准点的稳定性评价，是变形观测数据处理时不可忽视的重要内容。该文对基准点构网和不构网2种情况时的数据处理方法进行了探讨。  相似文献   

Anisotropic migration weight for amplitude-preserving migration and sensitivity analysis     

D. Kiyashchenko  B. Kashtan  R.-E. Plessix 《Geophysical Journal International》2004,157(2):753-763

  相似文献   

Study of statistically correcting model CMAQ-MOS for forecasting regional air quality     

XU Jianming  XU Xiangde  LIU Yu  DING Guoan  CHEN Huailiang  HU Jiangkai  ZHANG Jianchun  WU Hao  LI Weiliang  HE Jinhai  YANG Yuanqin  WANG Jiahe 《中国科学D辑(英文版)》2005,48(Z2)

Based on analysis of the air pollution observational data at 8 observation sites in Beijing including outer suburbs during the period from September 2004 to March 2005, this paper reveals synchronal and in-phase characteristics in the spatial and temporal variation of air pollutants on a city-proper scale at deferent sites; describes seasonal differences of the pollutant emission influence between the heating and non-heating periods, also significantly local differences of the pollutant emission influence between the urban district and outer suburbs, i.e. the spatial and temporal distribution of air pollutant is closely related with that of the pollutant emission intensity. This study shows that due to complexity of the spatial and temporal distribution of pollution emission sources, the new generation Community Multi-scale Air Quality (CMAQ) model developed by the EPA of USA produced forecasts, as other models did, with a systematic error of significantly lower than observations, albeit the model has better capability than previous models had in predicting the spatial distribution and variation tendency of multi-sort pollutants. The reason might be that the CMAQ adopts average amount of pollutant emission inventory, so that the model is difficult to objectively and finely describe the distribution and variation of pollution emission sources intensity on different spatial and temporal scales in the areas, in which the pollution is to be forecast. In order to correct the systematic prediction error resulting from the average pollutant emission inventory in CMAQ, this study proposes a new way of combining dynamics and statistics and establishes a statistically correcting model CMAQ-MOS for forecasts of regional air quality by utilizing the relationship of CMAQ outputs with corresponding observations, and tests the forecast capability. The investigation of experiments presents that CMAQ-MOS reduces the systematic errors of CMAQ because of the uncertainty of pollution emission inventory and improves the forecast level of air quality. Also this work employed a way of combining point and area forecasting, i.e. taking the products of CMAQ for a center site to forecast air pollution for other sites in vicinity with the scheme of model products "reanalysis" and average over the "area".  相似文献   

GPS精密卫星钟差估计研究     

孟范伟 《测绘与空间地理信息》2016,(9):77-79

随着精密单点定位技术的发展,对于精确的卫星坐标以及卫星钟差改正精度的要求越来越高,精密卫星星历以及精密卫星钟差的求解成为制约精密单点定位技术发展的瓶颈。本文基于修复周跳的载波相位观测值与相位平滑伪距观测值,采用无电离层延迟星间单差精密卫星钟差估计模型,在先估计出整周模糊度后,进行了精密卫星钟差的估计,并采用与IGS事后精密钟差作二次差的方法进行精度分析,这对于提高精密单点定位精度具有一定的意义。  相似文献   

北斗三频伪距相关随机模型单站建模方法     

黄令勇  吕志平  吕浩  宫轶松 《测绘学报》2016,45(Z2):165-171

为了提供可靠的伪距随机模型,基于3个线性无关的北斗三频伪距/载波无几何无电离层(GIF)组合,研究了一种利用单站数据估计北斗三频伪距相关随机模型算法。该算法首先利用低阶多项式对GIF组合进行拟合,以尽可能消除非伪距噪声以外的其他常数和误差,然后利用多元线性回归分析实现对3个线性无关的GIF组合随机噪声同时建模,最后再由线性组合关系变换得到原始北斗三频伪距相关随机模型。经北斗三频实测数据验证结果表明,该算法可实现北斗非差三频伪距相关随机模型的单站解算,有利于为导航定位以及完好性监测提供精准随机模型。  相似文献