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Physical and Meteorological Characteristics Associated with Lightning Ground Flashes: The National Lightning Detection Network and the Canadian Lightning Detection Network

与闪电地闪相关的物理和气象特征：国家闪电探测网络和加拿大闪电探测网络

基本信息

批准号：
0119476
负责人：
Richard Orville
金额：
$ 43.05万
依托单位：
Texas A&M Research Foundation
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2001
资助国家：
美国
起止时间：
2001-10-01 至 2005-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0119476&HistoricalAwards=false
关键词：
Physical Meteorological Characteristics Associated Lightning

项目摘要

This grant supports a continuation of the analysis of lightning flash and stroke characteristics across the United States using data from the National Lightning Detection Network (NLDN). These data extend back to 1983. To the American data will be added data from the Canadian Lightning Detection Network (CLDN), which was established in 1997. The two networks combined comprise 187 sensors and provide data extending from 25 degrees to 60 degrees N latitude and from 50 degrees to 135 degrees W longitude. The number of recorded flashes on these networks exceeds 300 million. The data are used for characterizing different properties of cloud-to-ground lightning, including flash polarity, the number of flashes per unit area, the peak current, and stroke multiplicity. Studies are under way on the variation of these quantities with season and geographical location, and their dependence on local features such as mountains and cities. There is already evidence of increased flash rates over urban areas, explained perhaps by increased convection over heated cities or by microphysical effects of pollution aerosols. Other findings to now are that the highest peak currents are in the upper Midwest and the highest percentage of positive flashes to ground are along the West Coast of the United States. Physical explanations for these findings will be sought as part of the project.

这笔赠款支持使用国家闪电探测网络（NLDN）的数据继续分析美国各地的闪电和中风特征。这些数据可以追溯到1983年。除美国的数据外，还将增加1997年建立的加拿大闪电探测网络（CLDN）的数据。这两个网络结合起来包括187个传感器，提供从北纬25度到60度以及西经50度到135度的数据。这些网络上记录的闪光次数超过3亿次。这些数据用于表征云地闪电的不同特性，包括闪电极性、单位面积闪电数量、峰值电流和雷击多样性。目前正在研究这些数量随季节和地理位置的变化及其对山区和城市等当地特征的依赖性。已经有证据表明，城市地区的闪光频率增加，这可能是由于城市上空的对流增加或污染气溶胶的微物理效应。到目前为止的其他发现是，最高的峰值电流在上中西部，最高百分比的正闪到地面是沿着美国西海岸。作为该项目的一部分，将寻求对这些发现的物理解释。