Journal of Earth System Science ( IF 1.3 ) Pub Date : 2021-09-03 , DOI: 10.1007/s12040-021-01670-7 N Kouassi 1 , V Doumbia 1 , K Boka 1 , Z Tuo 1 , O D F Grodji 1 , A A Kassamba 1 , A F Zillé 1
Research highlights
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Similar fluctuations in the time derivatives \(dH/dt\) and \(dD/dt\) of the geomagnetic field components were observed in the horizontal components \(Ey\) and \(Ex\) of the geoelectric field and the GIC variations.
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The disturbance fluctuations in the geoelectric field components and the GIC exhibit higher amplitudes during the daytime, especially between about 8:00 and 16:00 LT.
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The impulses in the geoelectric field components and the estimated GIC during this daytime are stronger in the southern stations than in the northern stations.
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On the average, the impulses in geoelectric field components and the estimated GIC exhibit a slight enhancement near the magnetic equator.
Abstract
In this paper, we analyzed low latitude geoelectric field variations and Geomagnetically Induced Current (\(GIC\)), associated with disturbed geomagnetic field variations in West Africa. For this purpose, variations of geomagnetic field components \(H\), \(D\) and \(Z\), and geoelectric field horizontal components \(Ey\) and \(Ex\) were examined during geomagnetically disturbed periods, with the daily means of the Ap index higher than 20 nT. Variations of geoelectric field components \(Ey\) and \(Ex\) were identified as associated with disturbed variations of the geomagnetic field. The \(GIC\) was estimated from the observed \(Ey\) and \(Ex\) based on system parameters configuration with \(a = b = 50~\,{\text{A}}\,{\text{km/V}}\). The disturbance fluctuations in the geoelectric field components and the estimated GIC exhibit a diurnal trend, with higher amplitudes during the daytime. The impulses in the geoelectric field components and the estimated \(GIC\) are stronger in the southern stations than in the northern stations. On the average, these impulses decrease from LAM to TOM, with a slight enhancement near the magnetic equator.
中文翻译：
与低纬度干扰地磁场变化相关的地磁感应效应
研究亮点
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在地电场和 GIC的水平分量\(Ey\)和\(Ex\)中观察到地磁场分量的时间导数\(dH/dt\)和\(dD/dt\)的类似波动变化。
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地电场分量和 GIC 的扰动波动在白天表现出更高的幅度，特别是在 LT 8:00 到 16:00 之间。
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南部站的地电场分量和白天估计的 GIC 中的脉冲比北部站强。
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平均而言，地电场分量中的脉冲和估计的 GIC 在磁赤道附近表现出轻微的增强。
抽象的
在本文中，我们分析了与西非扰动地磁场变化相关的低纬度地电场变化和地磁感应电流 ( \(GIC\) )。为此，在地磁扰动期间检查了地磁场分量\(H\)、\(D\)和\(Z\)以及地电场水平分量\(Ey\)和\(Ex\) 的变化， Ap 指数的日均值高于 20 nT。地电场分量\(Ey\)和\(Ex\) 的变化被确定为与地磁场的扰动变化有关。的\（GIC \）是根据观察到的\(Ey\)和\(Ex\)估计的，基于系统参数配置\(a = b = 50~\,{\text{A}}\,{\text{km/V}} \)。地电场分量的扰动波动和估计的GIC呈现出昼夜趋势，在白天具有更高的幅度。南部站的地电场分量和估计的\(GIC\)中的脉冲比北部站强。平均而言，这些脉冲从 LAM 到 TOM 减少，在磁赤道附近略有增强。
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