Prediction of geomagnetically induced currents (GICs) plays a critical role in the gestalt of space weather forecasting and risk assessment, giving power companies time to enact mitigation strategies that could avoid a catastrophic collapse of the power grid caused by, for example, the impact of an Earth-directed coronal mass ejection. Sun-to-mud prediction of the surface magnetic field (and/or its time derivative) is a long-standing goal for both first-principles and data-driven models. Here, we quantify the upper limits of peak GIC predictability as a function of how much magnetic field information is accurately predictable. Using the United States as a testbed, our results suggest that accurate characterization of temporal scales up to around 30 mHz keeps relative peak GIC errors below 10 across the regions considered. We also found that forecasting if GIC will exceed a specified threshold over the next 30 min is feasible with an accurate prediction of peak dB/dt magnitude. This is supported by reasonable out-of-sample performance across several forecast metrics (0.4–0.8 POD, POFD 0.05, 1–5 forecast ratio, 0.4–0.8 Heidke skill score), and favorable performance relative to a persistence model across all but the most extreme data intervals. We also find that the subsurface conductivity may influence peak GIC predictability. Overall, our results highlight the range of temporal scales in the surface magnetic field that are important for estimation of peak GIC and, in the context of peak dB/dt magnitude prediction, provide an upper bound on expected GIC predictability across a wide range of magnitudes.

中文翻译：

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作为可用磁场信息的函数的地磁感应电流的可预测性

地磁感应电流 (GIC) 的预测在空间天气预报和风险评估的格式塔中起着至关重要的作用，使电力公司有时间制定缓解策略，以避免电网的灾难性崩溃。地球定向的日冕物质抛射。表面磁场（和/或其时间导数）的太阳到泥浆预测是第一性原理和数据驱动模型的长期目标。在这里，我们将峰值 GIC 可预测性的上限量化为可准确预测的磁场信息量的函数。以美国作为试验台，我们的结果表明，对高达 30 mHz 左右的时间尺度进行准确表征可使相对峰值 GIC 误差保持在 10 以下跨考虑的区域。我们还发现，通过准确预测峰值 dB/dt 幅度，预测 GIC 是否会在接下来的 30 分钟内超过指定的阈值是可行的。这是通过合理外的样品性能跨越几个预测指标（支持0.4-0.8 POD，POFD 0.05，1-5预测比，0.4–0.8 Heidke 技能得分），以及相对于除最极端数据区间之外的所有持久性模型的良好性能。我们还发现地下电导率可能会影响峰值 GIC 的可预测性。总体而言，我们的结果突出了表面磁场中的时间尺度范围，这些范围对于估计峰值 GIC 很重要，并且在峰值 dB/dt 幅度预测的背景下，提供了在广泛幅度范围内预期 GIC 可预测性的上限.