A compilation is made of the largest and second‐largest magnetic‐storm‐maximum intensities, −Dst₁ and −Dst₂, for solar cycles 14–24 (1902–2016) by sampling Oulu Dcx for cycles 19–24, using published −Dst_m values for 4 intense storms in cycles 14, 15, and 18 (1903, 1909, 1921, 1946), and calculating 15 new storm‐maximum −Dst_m values (reported here) for cycles 14–18. Three different models are fitted to the cycle‐ranked −Dst₁ and −Dst₂ values using a maximum‐likelihood algorithm: A Gumbel model, an unconstrained Generalized‐Extreme‐Value model, and a Weibull model constrained to have a physically justified maximum storm intensity of −Dst_m = 2500 nT. All three models are good descriptions of the data. Since the best model is not clearly revealed with standard statistical tests, inference is precluded of the source process giving rise to storm‐maximum −Dst_m values. Of the three candidate models, the constrained Weibull gives the lowest superstorm occurrence probabilities. Using the compiled data and the constrained Weibull model, a once‐per‐century storm intensity is estimated to be −Dst₁ = 663 nT, with a bootstrap 68% confidence interval of [497, 694] nT. Similarly, the probability that a future storm will have an intensity exceeding that of the March 1989 superstorm, −Dst_m > 565 nT, is 0.246 per cycle with a 68% confidence interval of [0.140, 0.311] per cycle. Noting (possibly slight) ambiguity in the rankings of storm intensities, using the same methods, but storms more intense than those identified for cycles 14–16, would yield a higher once‐per‐century intensity and a higher probability for a −Dst_m > 565 nT storm.

中文翻译：

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从太阳周期14-24的历史Dst强度的等级统计得出的极端事件电磁风暴概率

通过发布19−24周的Oulu Dcx样本，对太阳周期14–24（1902–2016）的最大和第二大磁暴最大强度− Dst ₁和− Dst ₂进行了汇总。在第14、15和18个周期（1903、1909、1921、1946）中发生4次强风暴的Dst _m值，并为第14-18个周期计算15个新的风暴最大值-Dst _m值（此处报告）。循环排序的Dst ₁和Dst ₂安装了三种不同的模型使用最大似然算法得出的值：一个Gumbel模型，一个无约束的广义极限值模型和一个Weibull模型，其物理上合理的最大风暴强度为-Dst _m  = 2500 nT。这三个模型都是对数据的良好描述。由于最好的模型无法通过标准的统计测试清楚地揭示出来，因此无法推断出源过程，从而导致风暴最大值-Dst _m值。在这三个候选模型中，受约束的威布尔给出了最低的超级风暴发生概率。使用编译的数据和受约束的威布尔模型，每百年一次的风暴强度估计为-Dst ₁ = 663 nT，自举的68％置信区间为[497，694] nT。同样，未来风暴的强度可能会超过1989年3月的超级风暴-Dst _m > 565 nT，为每周期0.246，且每个周期的[0.140，0.311]的置信区间为68％。使用相同的方法，注意到（可能略有）风暴强度等级中的歧义，但是比14-16周期确定的风暴强度更大的风暴，将产生更高的百年一次强度和更高的-Dst _m概率。 > 565 nT暴风雨。