Abstract. Seasonal features of geomagnetic activity and their solar wind-interplanetary drivers are studied using more than 5 solar cycles of geomagnetic activity and solar wind observations. This study involves a total of 1239 geomagnetic storms of varying intensity identified using the Dst index from January 1963 to December 2019, a total of 75863 substorms identified from the SML index from January 1976 to December 2019, a total of 145 high-intensity long-duration continuous auroral electrojet (AE) activity (HILDCAA) events identified using the AE index from January 1975 to December 2017. The occurrence rates of the substorms, geomagnetic storms, including moderate (−50 nT ≥ Dst > −100 nT) and intense (−100 nT ≥ Dst > −250 nT), exhibit a significant semi-annual variation (periodicity ~ 6 months), while the super storms (Dst ≤ −250 nT) and HILDCAAs do not exhibit any clear seasonal feature. The geomagnetic activity indices Dst and ap exhibit a semi-annual variation while AE exhibits an annual variation (periodicity ~ 1 year). The annual and semi-annual variations are found to be driven by the annual variation of the solar wind speed V_sw and the semi-annual variation of the coupling function V B_s (where V = V_sw, and B_s is the southward component of the interplanetary magnetic field), respectively. We present a detailed analysis of the annual and semi-annual variations and their dependencies on the solar activity cycles separated as the odd, even, weak and strong solar cycles.

中文翻译：

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地磁活动的季节性特征：太阳活动依赖性的证据？

摘要。使用超过 5 个太阳周期的地磁活动和太阳风观测来研究地磁活动的季节性特征及其太阳风行星际驱动因素。本研究共涉及1963年1月至2019年12月使用Dst指数识别的不同强度地磁暴1239次，1976年1月至2019年12月SML指数识别的亚暴共75863次，高强度长- 1975 年 1 月至 2017 年 12 月期间使用 AE 指数确定的持续时间连续极光电喷射 (AE) 活动 (HILDCAA) 事件。亚暴、地磁暴的发生率，包括中度 (-50 nT ≥ Dst > -100 nT) 和强 ( −100 nT ≥ Dst > −250 nT)，表现出显着的半年变化（周期 ~ 6 个月），而超级风暴 (Dst ≤ −250 nT) 和 HILDCAAs 没有表现出任何明显的季节性特征。地磁活动指数 Dst 和 ap 呈现半年变化，而 AE 呈现年度变化（周期~1 年）。发现年度和半年度变化是由太阳风速的年度变化驱动的V _sw和耦合函数VB _s的半年变化（其中V  =  V _sw，B _s是行星际磁场的南向分量）。我们详细分析了年度和半年度变化及其对太阳活动周期的依赖性，这些周期分为奇数、偶数、弱太阳周期和强太阳周期。