In this study, solar ultraviolet (UV) radiation data collected in Riyadh, Saudi Arabia, between 2015 and 2022 were analyzed to explore quasi-periodicities in the UV time series. The power spectrum density analysis revealed several local peaks that exceeded the 95% confidence interval. These peaks included periodicities of 483–490 days, 272 days, 157−162 days, 103−110 days, 64–72 days, 27 days, and 13 days. To investigate the potential influence of space weather parameters on UV radiation, data on cosmic rays, solar radio flux at 10.7 cm (F10.7 cm), the Kp index, and solar wind speed for the same time period were examined. The aim was to identify periodicities in these variables that aligned with those found in the UV radiation data. The analysis reveals that several periodicities observed in the UV radiation spectrum are also present in the spectra of the considered parameters. Prominent periodicities include a 270-day cycle in UV radiation and cosmic rays, as well as periodicities of 72 days, 27 days, and 13 days in all considered variables. Furthermore, 110-day peaks are observed in spectrum of the UV radiation, the Kp index, solar radio flux F10.7, and solar wind speed. Notably, consistent peaks at 157-day periodicity are identified in the UV spectrum, also present in the spectra of all the considered variables (cosmic rays ∼162 days, Kp index ∼162 days, solar radio flux ∼156 days, and solar wind speed ∼163 days). The identification of common periodicities between UV radiation and space weather parameters in this study provides compelling evidence of a potential direct or indirect influence of solar variations on UV radiation. This finding significantly enhances our understanding of the impact of extraterrestrial factors, particularly solar activity, on the Earth’s environment.

中文翻译：

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紫外线辐射准周期性及其与宇宙线和太阳行星际数据的可能联系

在这项研究中，分析了 2015 年至 2022 年在沙特阿拉伯利雅得收集的太阳紫外线 (UV) 辐射数据，以探索紫外线时间序列的准周期性。功率谱密度分析揭示了几个超过 95% 置信区间的局部峰值。这些峰值的周期包括 483-490 天、272 天、157-162 天、103-110 天、64-72 天、27 天和 13 天。为了研究空间天气参数对紫外线辐射的潜在影响，我们检查了同一时间段的宇宙射线、10.7 厘米（F10.7 厘米）太阳辐射通量、Kp 指数和太阳风速数据。目的是确定这些变量中与紫外线辐射数据中发现的周期性相一致的周期性。分析表明，在紫外辐射光谱中观察到的几个周期性也存在于所考虑参数的光谱中。突出的周期性包括紫外线辐射和宇宙射线的 270 天周期，以及所有考虑的变量的 72 天、27 天和 13 天的周期。此外，在紫外线辐射光谱、Kp指数、太阳辐射通量F10.7和太阳风速中观察到110天的峰值。值得注意的是，在 UV 光谱中发现了 157 天周期性的一致峰值，也存在于所有考虑变量的光谱中（宇宙射线~162 天、Kp 指数~162 天、太阳射电通量~156 天和太阳风速） 〜163天）。本研究中确定的紫外线辐射和空间天气参数之间的共同周期性提供了令人信服的证据，证明太阳变化对紫外线辐射的潜在直接或间接影响。这一发现极大地增强了我们对地外因素（特别是太阳活动）对地球环境影响的理解。