Statistical analysis of spatial and temporal variations in atmospheric electric fields from a regional array of field mills
Statistical analysis of spatial and temporal variations in atmospheric electric fields from a regional array of field mills
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DOI：
10.1002/2016jd025944
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发表时间：
2017-01
期刊：
影响因子：
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通讯作者：
Guillaume Lucas;J. Thayer;W. Deierling
中科院分区：
文献类型：
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作者：
Guillaume Lucas;J. Thayer;W. Deierling
已经在地球仪周围的不同位置和时间段测量了全球电路的电场和电流，但是从未执行过来自电场米尔斯的区域阵列的长期分析。位于佛罗里达的肯尼迪航天中心（KSC）拥有30多个电场米尔斯，这些电场已经连续运行和存档数据超过18年。KSC还配备了许多气象塔。通过对长期数据集的初步统计分析，报告了四个独特的观察结果，包括全球和局部效应。为了定量描述这种效应，开发了一个模型来确定近表面电场，并将空间电荷和电导率扰动结合起来。使用空间阵列对米尔斯进行的统计自主分组表明，由海岸附近产生的风平流空间电荷引起的沿海到内陆米尔斯的空间变化大于50 V/m。时间分析确定了一个强大的，全球产生的，昼夜签名，但只有一个弱的年度信号被发现。一个现实的限制，电导率降低云内通过分析头顶云量与近地面电场强度。云内电导率降低的估计值约为1/3，与观测值相似，但明显低于微物理云估计值。最后，在日出时电场的增强在统计上与低风速和高相对湿度相关。本文提供了局部环境对近地表电场影响的统计描述，以作为未来研究的基础。
Electric fields and currents of the global electric circuit have been measured at different locations and time periods around the globe, but a long‐term analysis from a regional array of electric field mills has never been performed. Kennedy Space Center (KSC) in Florida has an array of over 30 electric field mills that have been continuously operating and archiving data for over 18 years. KSC is also instrumented with many meteorological towers. With this initial statistical analysis of a long‐term data set four unique observations are reported that encompass global as well as local effects. To quantitatively describe the effects, a model to determine near‐surface electric fields, incorporating space charge, and conductivity perturbations is developed. Statistical autonomous grouping of the mills using the spatial array demonstrates a greater than 50 V/m spatial variation from coastal to inland mills caused by wind‐advected space charge generated near the coast. A temporal analysis identified a strong, globally generated, diurnal signature, but only a weak annual signal is found. A realistic limit on conductivity reductions within clouds is estimated by analyzing overhead cloud cover in relation to near‐surface electric field strengths. The estimated in‐cloud conductivity reduction of approximately 1/3 is similar to observations but appreciably less than values estimated from microphysical cloud estimates. Finally, an enhancement in the electric field at sunrise is statistically well correlated with low wind speeds and high relative humidities. This paper provides a statistical description of local environmental effects on near‐surface electric fields by which to base future studies.