The temporal variation of the approximately 155-day Rieger solar periodicity, first detected in solar-flare data, is investigated in the Mg ii spectral emission as observed at 280 nm during the interval between 1980 and 2019. Daily mean values of Mg ii at each annual interval are spectrally analysed using Lomb–Scargle and Morlet wavelet techniques to obtain the temporal behaviour of particularly the ≈ 155-day Rieger as well as the \(\approx 27\)-day solar-rotation periodicities. Results obtained indicate substantial power in the Rieger periodicity that varies on an annual basis. In particular we found that the power of the Rieger periodicity exceeds that of the 27-day period during the maxima of Solar Cycles 21 (1981), 22 (1992), and 23 (2001), with the power of the 27-day periodicity dominating during the minima of these cycles. In contrast to these findings, we observe a substantial increase in power of the Rieger periodicity in comparison to that of the ≈ 27-day solar-rotation period during the minima of Solar Cycles 23 (2006, 2007) and 24 (2018, 2019). We report the first detection of the ≈ 1.3-year period as well as the temporal behaviour of the ≈ 155-day Rieger periodicity in Mg ii at 280 nm.

大约155天丽格太阳能周期性的时间变化，在太阳能耀斑数据首先检测，在Mg的研究 II在1980年和2019年的Mg的日平均值之间的间隔期间，在280nm处观察到的光谱发射 II在每个使用Lomb–Scargle和Morlet小波技术对年间隔进行频谱分析，以获得特别是≈155天Rieger以及\（\ approx 27 \）的时间行为天的太阳旋转周期。获得的结果表明，在Rieger周期中，每年都有很大的变化。特别是，我们发现在太阳周期21（1981），22（1992）和23（2001）的最大值期间，里格周期的幂超过27天周期的幂，其中27天周期的幂在这些周期的最小值中占主导地位。与这些发现相反，与太阳周期23（2006、2007）和24（2018、2019）的最小值期间的约27天太阳旋转周期相比，我们发现Rieger周期的功率大大增加了。我们报告了第一次检测到≈1.3年的时间，以及在280 nm的Mg ii中≈155天的Rieger周期性的时间行为 。