Sensitivity of Ground Magnetometer Array Elements for GIC Applications I: Resolving Spatial Scales With the BEAR and CARISMA Arrays
Sensitivity of Ground Magnetometer Array Elements for GIC Applications I: Resolving Spatial Scales With the BEAR and CARISMA Arrays
复制标题
GIC 应用的地面磁力计阵列元件的灵敏度 I：使用 BEAR 和 CARISMA 阵列解析空间尺度
作者：
S. Dimitrakoudis;D. Milling;A. Kale;I. Mann
地磁感应电流（Geomagnetically Induced Current，GIC）是由地磁扰动（GMD）产生的感应电场驱动的，而地磁扰动是磁层-电离层-地面耦合系统动力学的结果。然而，一个关键问题是评估磁力计站的最佳间距，以便对与GIC有关的GMD进行适当监测。在这里，我们评估GMD的矢量相关长度和相关的幅度发生分布的水平磁场的变化dBH/dt。具体而言，我们使用来自两个磁强计阵列的数据研究GMD对两个风暴时间亚暴的响应，斯堪的纳维亚的波罗的海电磁阵列研究项目和北美的加拿大阵列实时调查磁活动阵列，以确定合适的磁强计在纬度和经度上的间距，用于监测和评估GIC风险。我们发现，尽管在中纬度地区，磁扰动在几百公里的距离内具有很好的相关性，但在极光椭圆内，距离小于100公里的站的矢量相关长度迅速下降。一般来说，地磁波动在极光区更强，更局部化。由于极光椭圆在强烈的磁暴期间被推向赤道，我们强调，网络使用的站间距为10200公里，应提供一个很好的基础，监测小规模和大规模的地磁扰动。建议采用这种站间距的监测网络，以评估GMD在驱动电网GIC中的作用。
Geomagnetically induced currents (GICs) can be driven in terrestrial electrical power grids as a result of the induced electric fields arising from geomagnetic disturbances (GMD) resulting from the dynamics of the coupled magnetosphere‐ionosphere‐ground system. However, a key issue is to assess an optimum spacing for the magnetometer stations in order to provide appropriate monitoring of the GIC‐related GMD. Here we assess the vector correlation lengths of GMD and related amplitude occurrence distribution of the variations of horizontal magnetic field dBH/dt. Specifically, we study the GMD response to two storm‐time substorms using data from two magnetometer arrays, the Baltic Electromagnetic Array Research Project in Scandinavia and the Canadian Array for Realtime Investigations of Magnetic Activity array in North America, so as to determine the appropriate magnetometer spacing in latitude and longitude, for monitoring and assessing GIC risk. We find that although magnetic disturbances are well‐correlated up to distances of several hundred kilometers at mid‐latitudes, the vector correlation length rapidly drops off for station separations of less than 100 km within the auroral oval. In general geomagnetic fluctuations are stronger and more localized in the auroral zone. Since the auroral oval is pushed equatorward during intense magnetic storms, we highlight that networks using a station separation of ∼200 km should provide an excellent basis for monitoring both small and large scale geomagnetic disturbances. A monitoring network with this station spacing is recommended as being appropriate for assessing the role of GMD in driving GICs in the electric power grid.