雷击风险评估中L_o损失因子在多线路系统下的细化和改进          下载免费PDF全文

植耀玲  冯民学  樊荣 《气象科学》2012,32(3):298-303

2008年推广施行的新国标GB/T 21714.2已广泛应用于各地雷击风险评估业务中。但在实际应用过程中人们也发现用其建立评估模型时,标准的一些简约化约定,使得其计算结果不够精准,特别是描述和处理也显得越来越困难,影响和制约了它的应用范围和前景。为此,本文针对带有多种电气和电子系统的复杂结构建筑,提出按其进线分布特点,对Lo损失因子取值方法进行改进(下文均称"Lo优化取值法"),为多线路进线建筑物的雷击风险管理提供更细化的依据和算法,并举例证实。结果表明:细化考虑不同线路的Lo对于建筑物雷击风险评估更为切近真实。  相似文献   

闪电定位仪在人影作业中的应用研究   总被引：1，自引：0，他引：1  

贾显锋  郑传新 《气象研究与应用》2005,26(3):33-35

利用闪电定位仪系统所提供的多站综合定位资料和单站定位实况资料,结合9210系统所提供的卫星云图、雷达回波图以及T 213和日本的数值预报等资料,在做出24h降水预报的基础上,用闪电数据、云图等资料可制作未来3h降水预报。根据3h预报对作业点的作业条件进行指示,从而可为人影作业服务。经过试用验证表明,研究结果对人影作业有较好的指示意义。  相似文献   

山西离柳集团化肥厂雷击原因分析及防雷方案     

周伟  金梅  温汉光  林利娥 《山西气象》2009,(1):32-34

离柳集团化肥厂几乎每年均遭受雷害侵袭造成较大损失。本文对雷击原因（特别是DCS系统雷击原因）进行了系统分析并提出综合防雷方案。该方案2007年实施后取得良好的防雷效果。  相似文献   

新一代天气雷达资料传输说明及设置技巧          下载免费PDF全文

杨辉  姜宗元  朱敏武 《陕西气象》2009,(1):40-41

山西省人工降雨防雹办公室在山西省布设了雷电监测定位系统,在全省7个子站配备了ADTD雷电探测仪,并通过CDMA无线传输和气象系统局域网传输的方式将所探测的闪电数据传输到山西省人工降雨防雹办公室,以达到对雷电天气的实时监控．在数据上传国家探测中心的同时,也为我们飞行作业计划的制定提供了非常重要的指导作用。本文主要介绍了雷电定位系统的构成以及故障检查和处理。  相似文献   

中国中小尺度强对流天气气候学特征     

薛晓颖  任国玉  孙秀宝  任玉玉  余予 《气候与环境研究》2019,24(2):199-213

中小尺度强对流天气具有极强的破坏力,了解其气候学特征对于预测、预报和影响评价都具有实际意义。利用1961~2015年的2332个高密度逐月国家级气象站观测资料,分析了中国大陆3种常见中小尺度强对流天气（雷暴、闪电、冰雹）在年、季、月尺度上发生日数的时间变化规律和空间分布特征。结果表明:全国年平均雷暴、闪电和冰雹发生频率分别为39.23 d/a、20.56 d/a和1.07 d/a;雷暴和闪电主要发生在夏季3个月,雷暴日数7月最多,闪电日数8月最多;冰雹主要发生每年5~9月,6月发生频率最高;雷暴和闪电的高发区分布基本一致,主要集中在华南和西南,青藏高原也是雷暴的高发区域之一;冰雹的高发区主要集中在青藏高原、内蒙古高原东部以及中西部山地,而东南沿海地区发生频率则较低。进一步分析发现,我国雷暴和冰雹出现频率随海拔高度增加而明显增加,冰雹和海拔高度有更好的对应关系,二者增加速率分别为2.87 d/500 m和1.80 d/500 m,表明地势高度对这两种强对流天气形成和发展具有重要影响。  相似文献   

In situ measurements of contributions to the global electrical circuit by a thunderstorm in southeastern Brazil     

Jeremy N. Thomas  Robert H. Holzworth  Michael P. McCarthy 《Atmospheric Research》2009,91(2-4):153-160

The global electrical circuit, which maintains a potential of about 280 kV between the earth and the ionosphere, is thought to be driven mainly by thunderstorms and lightning. However, very few in situ measurements of electrical current above thunderstorms have been successfully obtained. In this paper, we present dc to very low frequency electric fields and atmospheric conductivity measured in the stratosphere (30–35 km altitude) above an active thunderstorm in southeastern Brazil. From these measurements, we estimate the mean quasi-static conduction current during the storm period to be 2.5 ± 1.25 A. Additionally, we examine the transient conduction currents following a large positive cloud-to-ground (+ CG) lightning flash and typical − CG flashes. We find that the majority of the total current is attributed to the quasi-static thundercloud charge, rather than lightning, which supports the classical Wilson model for the global electrical circuit.  相似文献   

Corona processes and lightning attachment: The effect of wind during thunderstorms   总被引：1，自引：0，他引：1  

E.M. Bazelyan  Yu.P. Raizer  N.L. Aleksandrov  F. D'Alessandro   《Atmospheric Research》2009,94(3):436-447

A simple model of a glow corona occurring near the tip of a grounded electrode in a thundercloud electric field that can be enhanced by an approaching downward leader has been studied analytically and numerically with regard to the effect of wind. We obtained an approximate expression for corona current taking into account the (i) removal of space charge from the coronating point due to ion drift and wind and (ii) image of the charge in the ground. As the wind velocity decreases to zero, the expression tends to that obtained previously in the absence of wind. It was shown analytically and numerically that, in a thundercloud electric field, even moderate wind velocities lead to hundreds of percent increase in the corona current. This current decreases with time only slightly in a steady thundercloud electric field, as opposed to the current behavior in the absence of wind. However, even strong wind is not sufficient to affect the properties of a corona intensified in the electric field of an approaching downward leader. The occurrence of wind does not affect the conditions for initiation of an upward connecting leader from grounded objects and consequently the efficiency of lightning rods of ordinary height.  相似文献   

Analysis of microsecond- and submicrosecond-scale electric field pulses produced by cloud and ground lightning discharges     

Amitabh Nag  Brian A. DeCarlo  Vladimir A. Rakov 《Atmospheric Research》2009,91(2-4):316-325

We examined microsecond- and submicrosecond-scale pulses in electric field records of cloud and cloud-to-ground lightning discharges acquired in summer 2006, in Gainesville, Florida. A total of 12 cloud and 12 ground flashes were analyzed in detail, with the electric field record length being 96 or 200 ms and sampling interval being 4 or 10 ns. The majority of pulses in both cloud and ground discharges analyzed in this study were associated with the initial breakdown process and were relatively small in amplitude and duration. The typical durations were an order of magnitude smaller than tens of microseconds characteristic of “classical” preliminary breakdown pulses. We estimated that 26% of the pulses in the 12 cloud discharges and 22% of the pulses in the 12 cloud-to-ground discharges had total durations less that 1 µs.  相似文献   

The intracloud/cloud-to-ground lightning ratio in Southeastern Brazil     

P.E. de Souza  O. Pinto Jr.  I.R.C.A. Pinto  N.J. Ferreira  A.F. dos Santos 《Atmospheric Research》2009,91(2-4):491-499

The intracloud to cloud-to-ground lightning flash ratio (Z) has been estimated for the first time in Southeastern Brazil and in the tropical region using the Lightning Imaging Sensor (LIS) and Brazilian lightning detection network (BrasilDat) lightning data obtained from 1999 to 2005. Geographical variations of Z and their relation to elevation, latitude, precipitation, total lightning density and percentage of positive CG lightning will be discussed. Daily variations of Z will also be presented. The results suggest that Z values are similar to studies outside the tropics and that are influenced by orographic features.  相似文献   

雷击地闪密度与雷暴日数的关系分析   总被引：13，自引：4，他引：9  

马金福  冯志伟 《气象科学》2009,29(5):674-678

根据美国卫星观测得到的我国各省区年平均总闪电资料并计算出各省区的年平均地闪密度(以下简称地闪密度);根据全国各省区220个站点的年平均雷暴日资料,按照<建筑物防雷设计规范>GB50057-94(2000年版)(以下简称<规范>)公式计算出全国各省区的地闪密度.比较两种方法得出的地闪密度,发现存在较大的差异,且不同区域差异变化很大.用单位雷暴日地闪密度概念,分析了我国各地单位雷暴日地闪密度的差异及其原因,指出单位雷暴日地闪密度能粗略反映与我国气候特征相适应的地闪密度的分布状况.进一步分析湖州市2007年人工观测和闪电定位仪观测的闪电资料,得到相同的结论.从而提出<规范>规定的地闪密度计算公式存在较大误差,应对其进行进一步的修订和完善.  相似文献