北京地区不同天气条件下近地面大气电场特征   总被引：8，自引：2，他引：6       下载免费PDF全文

吴亭  吕伟涛  刘晓阳  董万胜  张义军  李成才  王美华  杨晶  李长河 《应用气象学报》2009,20(4):394-401

利用2004年8月—2005年11月近地面大气电场仪的观测资料, 对北京地区不同天气条件下近地面大气电场特征进行分析。结果表明:北京地区晴天近地面大气电场日变化呈双峰双谷, 谷值分别出现在北京时05:00和12:00, 峰值分别出现在07:00和23:00, 并且表现出一定的季节变化; 晴天大气电场的变化与气溶胶含量的变化有密切关系, 两者呈正相关; 晴天大气电场与绝对湿度之间也表现出很强的相关性, 在一定程度上反应了水汽对大气电场的作用; 沙尘天气下风速均达到一定强度, 近地面大气电场为负值, 并且变化剧烈, 电场强度与PM₁₀之间呈现较强的负相关, 而电场强度与风速之间没有表现出明显的相关性。  相似文献   

赴瑞典参加第29届国际雷电防护会议总结     

张义军  董万胜  吕伟涛 《气象科技合作动态》2008,(6)

2008年6月23～26日,第29届国际雷电防护会议（ICLP：International Conference on Lightning Protection,简称ICLP2008）在瑞典乌普萨拉（Uppsala）召开。ICLP是国际上关于雷电防护方法和技术研究方面最重要的学术交流活动之一,自1951年首次举办ICLP以来,ICLP一直致力于为全世界的科研和工程人员提供一个良好的交流平台,通过多学科之间的交叉融合,实现雷电防护方法和技术  相似文献   

青藏高原那曲地区雷电特征初步分析   总被引：32，自引：3，他引：29       下载免费PDF全文

赵阳  张义军  董万胜  张鸿发  陈成品  张彤 《地球物理学报》2004,47(3):405-410

通过对2002年夏季青藏高原那曲地区雷暴过程及闪电观测资料的初步分析,发现该地区雷暴电荷结构具有多样性和复杂性,地闪明显偏少. 对高原地闪的一些基本特征参量的统计分析表明,无论正地闪还是负地闪梯级先导前都具有持续时间较长的云内放电过程,地闪以单次回击为主. 与中低纬度地区相比,高原地闪中正地闪比例明显要高,为33髎;负地闪为67髎;正、负地闪回击后常常伴随短时间的连续电流.  相似文献   

洛杉矶连续的全球定位系统台阵有助于地震灾害评估吗？     

Pres.  WH 《世界地震译丛》1997,(1):82-82

景色美丽气候宜人的南加州是2000多万人口的家园,而且对国民经济非常重要。遗憾的是,该地区也纵横分布着许多可产生强烈地震的活断层。来自一些科研院所的科学家正在探索一种研究高危险性大都市地区地震灾害的新方法。 SCIGN(南加州综合全球定位系统台  相似文献   

Immigration impacts on internal migration of the poor: 1990 census evidence for U.S. states     

Frey WH 《International journal of population geography : IJPG》1995,1(1):51-67

"This article presents newly-available migration data from the 1990 U.S. census to assess immigration and internal migration components as they affect state poverty populations. New immigrant waves are heavily focused on only a few 'port-of-entry' states. It is suggested that these immigrants have begun to impact upon internal migration into and out of these 'high immigration states', and have also altered the national system of internal migration patterns. This article addresses three questions: How do the magnitudes of poverty population out-migration from high immigration states compare with those of other states? Is this out-migration selective on particular social and demographic groups? Is immigration a significant determinant of internal migration of the poor population? The results of this analysis are consistent with the view that recent, focused immigration is associated with out-migration among a state's poor longer-term residents."  相似文献   

云闪辐射脉冲序列的丛集特征     

苟学强  张义军  董万胜  陈明理 《高原气象》2008,27(3):644-647

根据2002年夏季那曲地区野外观测的宽带干涉仪资料, 应用变异系数CV、 Allan因子分析(AFA)和Fano因子分析(FFA)等统计方法, 对33个云闪辐射脉冲事件序列的时间丛集特征进行了分析.结果显示, 放电过程呈现强的分形丛集性, 变异系数平均为5.2, AFA和FFA标度指数αAF及αFF平均分别为1.42和0.81; 同时发现, 初始强K脉冲前CV增加到明显>1.  相似文献   

余震的早期预警系统     

Baku.  WH 陈时军 《世界地震译丛》1995,(4):77-83

一台预警系统的样机在１９８９年１０月２８日投入运行。该系统对１９８９年１０月１７日洛马普理塔７．１级地震后一系列余震的强地面震动在加州旧金山和奥克兰地区提供了几十秒钟的预警时间。该样机系统由四部分组成，即置于震中区的地动传感器、中央接收机、无线电中继器和无线电接收器。其中一台无线电接收机１０月２８日放置在位于已被破坏的加州奥克兰Ｉ－８８０高速公路赛普里斯路段的加州交通指挥总部大楼内，并在１９８９年  相似文献   

大陆“弱”转换断层邻近的扩张与沉陷：以东非鲁夸裂谷为例     

Whee.  WH 陈时军 《地震地质译丛》1995,17(1):5-10

鲁夸裂谷为一长３００公里的半地堑盆地，它沿东非裂谷内长达１０００公里的大陆转换断层中段分布。盆地含有厚达１１公里的石炭系至第四系地层。尽管此边界断层以右旋走向滑动为主，盆地内最大扩张方向近垂直于该断层。但裂谷的扩张与沉陷不能以释放弯曲和斜向拉伸断几何形来解释。我们把这种扩张方向性解释为低磨擦，“弱”走滑边界断层的局部应力旋转特征。沿边界断面走向的磨擦强度差异控制着扩张的部位，垂直于裂谷边界断层的沉  相似文献   

Observations on the leader-return stroke of cloud-to-ground lightning with the broadband interferometer     

董万胜  刘欣生  张义军  张广庶 《中国科学D辑(英文版)》2002,45(3):259-269

Radio frequency observations of cloud-to-ground lightning (CG) were made in 1999 in Guangdong Province with the broadband lightning interferometer. In this paper, radiation source locations and electric field waveforms are analyzed for different types of breakdown events, including the preliminary breakdown of in-cloud activities, the stepped leaders of initial strokes to ground and activities during and following return strokes. It is shown that the structure and development of lightning discharges and associated breakdown processes can be reconstructed by using this new type of lightning radiation source location system. The detectable radiation of lightning was primarily produced by the negative breakdown process. The channel was concentrated with few branches during the preliminary breakdown stage of CG lightning flashes. The radiation sources appeared generally at the tip of the channel. During the late period of the stepped leader, the radiation sources were dispersed with branches extended away from the main channel. The radiation sources were in a certain length segment of the channel and the altitude of the segment descended along with the propagation of the leader to the ground. During the preliminary breakdown and the stepped leader of initial strokes to the ground, a sequence of fast negative streamers were observed to start continually from or farther away the lightning-initiated region and propagate along the developed leader channel, which may supply negative charge that assisted the leader’s development. The progression speed of fast negative streamers was about ten times faster than the average speed of lightning channel.  相似文献   

1989—1991年发生在美国及其邻近地区的地闪的特征     

Orvi.  RE 董万胜 《大气情报》1997,17(1):14-21

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