Surface electric fields for North America during historical geomagnetic storms
Surface electric fields for North America during historical geomagnetic storms
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DOI：
10.1002/swe.20073
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发表时间：
2013-08
期刊：
影响因子：
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通讯作者：
Lisa H. Wei;N. Homeier;J. Gannon
中科院分区：
文献类型：
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作者：
Lisa H. Wei;N. Homeier;J. Gannon
为了更好地理解地磁扰动对电网的影响，我们从两次历史上的地磁风暴——1989年的“魁北克”风暴和2003年的“万圣节”风暴中重建了地表电场。使用球面初等电流系统方法，我们在北美插值稀疏分布的磁力计数据。我们发现实测数据与插值数据吻合良好，在高纬度地区，磁场变化越大，均方根偏差越大。将插值的磁场数据与来自美国地质调查局和文献的25个独特地理区域的表面阻抗相结合，以估计1分钟时间步长的水平正交表面电场。感应水平电场在很大程度上取决于当地的表面阻抗，导致大西洋和墨西哥湾沿岸的电场振幅惊人地强。对于不同的输入磁场时间序列，各地理区域的相对峰值电场幅值归一化为内陆平原地区的值，变化系数为2。然而，峰值电场振幅的顺序（从大到小）不太取决于输入。这些结果表明，在地磁感应电流的影响下，地磁纬度较低、地面电阻率较高的地区也处于危险之中。历史电场时间序列可用于估计长传输线中感应电流的流动，从而研究地磁扰动下的电力潮流和电网稳定性。
To better understand the impact of geomagnetic disturbances on the electric grid, we recreate surface electric fields from two historical geomagnetic storms—the 1989 “Quebec” storm and the 2003 “Halloween” storms. Using the Spherical Elementary Current Systems method, we interpolate sparsely distributed magnetometer data across North America. We find good agreement between the measured and interpolated data, with larger RMS deviations at higher latitudes corresponding to larger magnetic field variations. The interpolated magnetic field data are combined with surface impedances for 25 unique physiographic regions from the United States Geological Survey and literature to estimate the horizontal, orthogonal surface electric fields in 1 min time steps. The induced horizontal electric field strongly depends on the local surface impedance, resulting in surprisingly strong electric field amplitudes along the Atlantic and Gulf Coast. The relative peak electric field amplitude of each physiographic region, normalized to the value in the Interior Plains region, varies by a factor of 2 for different input magnetic field time series. The order of peak electric field amplitudes (largest to smallest), however, does not depend much on the input. These results suggest that regions at lower magnetic latitudes with high ground resistivities are also at risk from the effect of geomagnetically induced currents. The historical electric field time series are useful for estimating the flow of the induced currents through long transmission lines to study power flow and grid stability during geomagnetic disturbances.