浅论防雷接地电阻值的检测

在防雷检测实际工作当中,经常出现的接地电阻值读数偏大、偏小、甚至出现检测值为负值等不稳定的情况,该文通过分析各种接地电阻的检测方法、测试仪的工作原理及使用范围,结合工作实践经验,分析造成接地电阻测量值偏离真值的常见原因,浅论避免或减小接地电阻值偏离真值的方法。     

对两个接地电阻问题的探讨

1 工频接地电阻和冲击接地电阻 防雷检测工作中,检测防雷接地电阻是基本的工作,因此对接地电阻定义的理解和提高检测接地电阻值的准确度有着十分重要的意义.如检测某防雷装置接地电阻值超出规范要求时(在操作正确、仪器良好、考虑线阻和排除其他因素干扰的情况下),相当一部分检测人员往往会简单地认为该接地电阻不符合技术要求,其实通过检测得到的电阻值为工频接地电阻,而规范上所要求的接地电阻多为冲击接地电阻,如果混淆了二者的区别,易导致得出错误的结论.     

对两个接地电阻问题的探讨

1 工频接地电阻和冲击接地电阻 防雷检测工作中，检测防雷接地电阻是基本的工作，因此对接地电阻定义的理解和提高检测接地电阻值的准确度有着十分重要的意义。如检测某防雷装置接地电阻值超出规范要求时（在操作正确、仪器良好、考虑线阻和排除其他因素干扰的情况下），相当一部分检测人员往往会简单地认为该接地电阻不符合技术要求，其实通过检测得到的电阻值为工频接地电阻，而规范上所要求的接地电阻多为冲击接地电阻，如果混淆了二者的区别，易导致得出错误的结论。     

防雷接地检测特殊场地异常原因分析

分析了影响接地电阻的主要因素,介绍了接地电阻的测量方法、注意事项及不同检测对象对检测仪器的不同选择,并分析检测中接地电阻特殊场地出现异常的原因,提出具体解决办法.     

防雷接地电阻测量误差诊断

接地电阻是电流在流经接地装置到大地过程中所感测到的接地极的电阻,该电阻主要受土壤与接地极表面的接触电阻和靠近接地电极的大部分土壤的电阻影响。在日常的防雷设施检测中,接地电阻值是判断防雷装置性能优劣的重要技术指标之一,对接地电阻的测量,因各种因素的存在会产生不可避免的误差,但熟悉仪器的测量原理并正确操作,且认真选择辅助地极的位置就可以大大减小误差,从而避免接地阻值的读数不稳定、偏大或偏小,以确保雷电安全检测工作的有效性。因此有必要对影响接地阻值各种因素进行系统分析。     

接地电阻测量值的数据处理方法探讨

针对防雷装置接地电阻测量过程中出现的各种误差原因,文章介绍了防雷装置接地电阻测量值数据处理的几种方法,并通过实例进行了验证,以达到让目前的防雷检测工作更加规范和准确的目的.     

接地电阻值测试误差原因及对策

通过介绍接地电阻测试原理,分析了接地电阻测试工作中出现各种误差的原因,并指出了解决方法,对从事防雷检测工作的技术人员测量接地电阻具有参考作用。     

防雷设施检测中正确测量接地电阻方法探讨

本文针对目前防雷设施检测工作中出现的问题,从接地电阻测量的原理入手,提出几种测试方法和注意事项,以指导检测人员正确测量接地电阻,提高防雷检测机构的检测能力,增强检测人员的技术水平.     

防雷检测仪器的选用、使用和维修技巧

避雷针等防雷设施的接地电阻检测,是整个防雷工程的一部分,也是防雷工作的基础。而作为防雷检测的工具———接地电阻测试仪,更是防雷检测工作中必不可少的。防雷检测仪器由早期俗称“摇表”的机械手摇指针式,到电子指针式、电子液晶数码显示式,以及最新的电子遥感数码显示式（不用打铺助电极直接测量）。如何选好用好接地电阻测试仪,不仅是搞仪器供应人员关心的问题,相信也是广大防雷检测工作者所关心的问题,以下将对此进行探讨。１　接地电阻测试仪选用　　（１）机械手摇指针式接地电阻测试仪,俗称“摇表”,典型型号如上海产“…     

脉冲式接地电阻测试仪的使用技巧

简述脉冲式接地电阻测试仪的使用技巧,探讨在防雷检测的接地电阻测试中经常碰到的疑难问题,分析了出现这些问题可能原因,并给出了解决办法。     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment.     

Analysis of Atmospheric Boundary Layer Height Characteristics over the Arctic Ocean Using the Aircraft and GPS Soundings

正ERRATUM to: Atmospheric and Oceanic Science Letters, 4(2011), 124-130 On page 126 of the printed edition (Issue 2, Volume 4), Fig. 2 was a wrong figure because the contact author made mistake giving the wrong one. The corrected edition has been updated on our website. The editorial office is sincerely sorry for any     

Index to Vol.31

正AN Junling;see LI Ying et al.;(5),1221—1232AN Junling;see QU Yu et al.;(4),787-800AN Junling;see WANG Feng et al.;(6),1331-1342Ania POLOMSKA-HARLICK;see Jieshun ZHU et al.;(4),743-754Baek-Min KIM;see Seong-Joong KIM et al.;(4),863-878BAI Tao;see LI Gang et al.;(1),66-84BAO Qing;see YANG Jing et al.;(5),1147—1156BEI Naifang;     

Information for Contributors

正Journal of Meteorological Research is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press,sponsored by the Chinese Meteorological Society.It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists and aiming at introduction of the current advancements in atmospheric sciences in China.The journal columns include Articles.Note and Correspondence,and research letters.Contributions from all over the world are welcome.     

前寒武纪气候演化中的三个重要科学问题

自地球形成至寒武纪将近40亿年（距今46亿～5.4亿年,通常称为前寒武纪）的气候演变是一个具有特殊难度和挑战性的研究领域,同时也是基础和前沿的研究领域。文章选择了前寒武纪气候演化中的三个重要科学问题进行综述：大气演化、两次全球性的冰川期以及暗弱太阳问题。关于大气演化,本文首先描述了大气成分的演化历史,然后简述了影响大气成分演化的三个基本过程：大气逃逸、两次大气氧含量突然增加、碳酸盐-硅酸盐循环及其对气候系统的负反馈作用。两次全球性的冰川期分别发生在古元古代（距今24亿～21亿年）和新元古代（距今8亿～5.8亿年）,文章简述了其成因以及相关的气候模拟结果。暗弱太阳问题是地球历史气候演化的一个经典问题,论文简要地综述了一些最新的研究成果和观点。     

淮河流域水文极值预测模型研究

为探索气候变化影响下水文极值的非平稳性和预测方法,建立了水文极值非平稳广义极值（GEV）分布的统计预测模型。利用1952-2010年淮河上游流域累计面雨量和流量年最大值资料、同期500 hPa环流特征量资料以及17个CMIP5模式对环流特征量的模拟结果,筛选出对水文极值影响显著的年平均北半球极涡强度指数作为GEV分布参数的预测因子。分析了在RCP2.6、RCP4.5和RCP8.5情景下2006-2050年淮河上游流域水文极值对气候变化的响应。结果表明,10年以下与10年以上重现期的水文极值在非平稳过程中呈现前者下降而后者上升的相反变化趋势;多模型预测的集合平均在未来情景中均呈现上升趋势,情景排放量越大增幅越大,重现期越长增幅也越大。与极值的常态相比,极值的极端态更易受气候变化影响。     

CHARACTERISTICS AND TRENDS OF CLIMATIC EXTREMES IN CHINA DURING 1959–2014

The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms.