Helicity as a Method for Forecasting Severe Weather Events     

Ding Jincai  Dai Jianhu  Chen Yamin  Hu Fuquan  Tang Xinzhang 《大气科学进展》1996,13(4):533-538

This paper introduces a method for forecasting severe weather which is yieded by integrating helicity as a dynamical parameter with K and TOT indexes as thermal parameters.The results of operational tests for two years ure detailed.And the seasonal suitability of the method applications is discussed as well.  相似文献   

1992年四川力马地震序列期间激发的孕震结构   总被引：2，自引：1，他引：2  

赵珠  陈农 《中国地震》1996,12(1):64-74

对小震序列的深入研究或许可以作为对大震序列震后趋势研究的替代，本文将地震模拟量已转化为数字记录的马力小震序列来尝试这种替代。。  相似文献   

港澳地区对中国内地直接投资的区位选择及其空间扩散   总被引：29，自引：3，他引：29  

贺灿飞  陈颖 《地理科学》1997,17(3):193-200

对港澳地区在中国内地直接投资的空间分布及其空间转移做了上分析，表明了港澳地区对中国内地的直接投资趋向于沿海地区和与这这有特殊社会文化联系的区位，同时更有向中西部和北部转移的趋势，决定港澳地区对中国内地投资空间模式和转移态势的因素是经济规模，经济增长速率，劳动力因素，经济开放度，与沿海的经济距离等。  相似文献   

胶州湾环境与工程建设     

贾永刚  孙永福 《海岸工程》1996,15(2):29-36

系统地论述了胶州湾海底地形地貌特征，第四系沉积类型，空间分布，物理力学性质，基底岩石类型，构造发育状况，湾内水动力条件，讨论了湾内不同地区对工程建设适宜性。  相似文献   

2005年陕西第一场透雨诊断分析          下载免费PDF全文

梁生俊  侯建忠 《陕西气象》2007,(2):9-12

通过资料分析,得到运城市范围内大暴雨的分布地域,认识了大暴雨的产生是多种天气尺度相互作用的结果,提出大暴雨落区预报关键掌握850 hPa低空急流的建立,500 hPa西风带急流的出现,热带的副热带高压、台风的活动。  相似文献   

湖南省外商直接投资区位与全国各省市的比较     

余慧  贺清云 《热带地理》2007,27(6):543-547

以我国东、中、西部有典型代表的10省市与湖南省为研究对象,设定有代表性的区位因素指标,运用灰色关联对各省市外商直接投资区位进行实证分析,通过相关因素的横向分析和对比来探讨湖南省外商直接投资区位条件。结果表明:经济规模和市场容量、区域的全球化水平和外贸依存度、信息化发展程度和基础设施状况、地理区位和区位惯性基本上决定了外商直接投资在我国的区位选择;工业化水平、劳动力成本、城市化水平、市场化程度、第三产业发展水平对外商直接投资的区位选择有一定的影响。湖南省在信息化发展水平和基础设施、人力资源、科技、第三产业发展水平上有一定的优势,劣势则表现在外贸依存度、融资能力、工业化发展水平等。  相似文献   

苏州地区雷电分布规律分析   总被引：10，自引：3，他引：10  

李霞  汪庆森  巩晴霞  曾山泊  肖稳安 《气象科学》2006,26(4):442-448

利用苏州地区2002~2004年闪电定位系统监测资料,分析了该地区地闪的月变化、日变化、强度、闪电密度等特征。结果表明,苏州地区地闪的月变化呈单峰分布,而日变化则呈双峰分布,夏季19时左右是该地区强对流天气最易发展成熟的时段;雷电流强度不大于104A所占比例最大,强度大于104A的强雷电主要集中在南部地区,以正闪为主;苏州市区是闪电频发的中心地带;闪电多发区与当地的环境有很大关系。  相似文献   

Application of an improved algorithm to high precision relocation of ISC test events   总被引：1，自引：0，他引：1  

Eric Robert Engdahl 《Physics of the Earth and Planetary Interiors》2006,158(1):14-18

New location features for possible implementation by the International Seismological Centre in its standard location procedures are tested using a set of 156 well-located and geographically well-distributed earthquakes and explosions. The tests are performed using the Engdahl et al. ([Engdahl, E.R., Van der Hilst, R.D., Buland, R.P., 1998. Global teleseismic earthquake relocation with improved travel times and procedures for depth determination. Bull. Seism. Soc. Am. 88, 3295-3314]; EHB) location algorithm with the 1-D reference Earth model ak135 [Kennett, B.L.N., Engdahl, E.R., Buland, R., 1995. Constraints on seismic velocities in the Earth from travel times, Geophys. J. Int. 122, 108-124]. Weighting by phase variance as a function of distance improves location accuracy by 7%. Use of later phase arrival times does not result in a significant improvement in location or depth for events with observing stations well distributed in azimuth. However, with application of an improved phase identification technique, depth phases provide significantly better estimates of focal depth.  相似文献   

Using beamforming for the global network location     

V. Pinsky 《Physics of the Earth and Planetary Interiors》2006,158(1):75-83

The aim of this study is the design and trial of a novel sparse network beamforming (NB) technique to improve earthquake location. For this purpose bulletin phase arrival time data were processed via the use of complex exponents form and then used in an optimization via grid-search to search for the maximum semblance in hypocenter space. The use of the robust semblance statistic, provides reliable location results. The NB location results for a set of test events were compared to standard iterative ISC location procedure “iscloc” and its prototype the Jeffreys maximum likelihood estimator. For this purpose a data-base of 139 reference ground-truth events was extracted from the catalog of the International Seismological Centre (ISC) (97 GT5 events, assumed earthquakes, and 42 GT0 nuclear tests). The tuned NB procedure has shown excellent location results for events with a “good” ISC location and demonstrated the large epicenter deviations have been decreased in “bad” cases. Further developments of the algorithm would include allowances for 3D earth structure and a priori site-specific information.  相似文献   

上海台阵标定方法的对比研究          下载免费PDF全文

赵书礼  朱元清  于海英  宋治平 《地震工程学报》2006,28(2):118-122

本文介绍了基于台阵标定理论建立的上海台阵标定数据库;提出了最近标定和平均标定的方法。通过典型的地震事件对新方法进行了校验,结果表明最近标定和平均标定法的标定效果都比较好,有效的提高了地震定位精度。  相似文献