第21～24太阳周4类空间天气事件爆发特征统计分析

对第21～24太阳周不同等级的太阳X射线耀斑事件、太阳质子事件、地磁暴事件及高能电子增强事件的爆发频次特征进行统计，结果表明：太阳周耀斑爆发的总数量与该太阳周的黑子数峰值呈正比，耀斑总数、X级耀斑事件数与峰值的相关系数分别为0.974，0.997；太阳质子事件主要发生在峰年前后1～2年，约占总发生次数的80%，峰值通量大于10pfu （1 pfu=1 cm^-2·sr^-1·s^-1）的质子事件中，84%伴有耀斑爆发，并且主要伴随M或X级耀斑，少量伴随C级耀斑，峰值通量大于1000pfu的质子事件中，98%伴随M或X级耀斑，并且以X级耀斑为主；第21，22，23和24太阳周发生地磁暴最频繁的时间分别在1982，1991，2003年和2015年，分别滞后黑子数峰值时间3年、2年、2年和1年；72%的高能电子增强事件发生在太阳周下降期，24%的高能电子增强事件发生在太阳周上升期.

Statistical Analysis on Four Kinds of Space Weather Events during Solar Cycles 21~24

Based on the statistics of different intensity levels of solar X-ray flares, solar proton events, geomagnetic storms and relativistic electron flux enhancement of Solar Cycle 21~24, the following conclusions can be drawn. Firstly, the total number of X-ray flares in solar cycle is directly proportional to the number of sunspot maximum, and the correlation coefficients of the total number of flares, X-class flares and sunspot maximum are 0.974 and 0.997, respectively. Secondly, the solar proton events mainly occurred in the first two years before and after the peak year, accounting for 80% of the total number of events. 83% solar proton events with peak flux over 10 pfu (1 pfu=1 cm-2·sr-1·s-1) were mainly accompanied by X-class and M-class flares, but also with a small number of M-class flares. For the solar proton events with the peak flux over 1000 pfu, about 98% of them were accompanied by C-class flares. Thirdly, the most frequent time of geomagnetic storms occurred during Cycle 21, 22, 23 and 24 was in 1982, 1991, 2003 and 2015, respectively, which lagged behind the peak time of sunspot maximum by three years, two years, two years and one year, respectively. Finally, 72% of the relativistic electron flux enhancement occurred in the declining phase of solar cycle, and 24% of them occurred in the rising phase.