Global attention has been focused on extreme climatic changes. This paper investigates the relationship between different phases of solar activity and extreme precipitation events in Kerala, India. Sunspot number and rainfall data were analysed over 122 years (1901-2022) on an annual scale. A negative correlation was observed in the winter and post-monsoon seasons, while positive correlations were seen in the pre-monsoon and monsoon seasons, all of which were statistically significant. Using cross-wavelet transform, the temporal relationship between sunspot number and rainfall values was investigated, revealing significant cross-power at an 8-12 year scale across all seasons. Wavelet coherence between the two data sets demonstrated significant correlation at the 2-4 and 4-8 year scales throughout the four seasons. The results show that the seasonal rainfall over Kerala is related to solar activity. The solar phases of Solar Cycles 14-24 were determined for all seasons, and the years with excessive and insufficient rainfall were identified. It was observed that the descending phase had an impact on excess rainfall events during the winter and pre-monsoon seasons, while the ascending phase notably affected the monsoon and post-monsoon seasons. The study specifically examined the different magnetic polarities of sunspots in alternating solar cycles, focusing on even and odd cycles. It was found that extreme rainfall events were more frequent during the winter and pre-monsoon seasons in the even cycles, whereas in the odd cycles, they were more prevalent during the monsoon and post-monsoon seasons. These findings are presented for the first time and may offer new perspectives on how different phases affect rainfall. This study suggests a physical link between solar activity and extreme precipitation in Kerala, which could increase predictability.

翻译：全球关注焦点已集中于极端气候变化。本文研究了太阳活动不同阶段与印度喀拉拉邦极端降水事件之间的关系。基于122年（1901-2022年）的年尺度数据，对太阳黑子数与降雨量进行了分析。冬季和季风后季节呈现显著负相关，而季风前和季风季节则呈现显著正相关。通过交叉小波变换探究太阳黑子数与降雨值的时间关联性，发现所有季节在8-12年尺度上均存在显著的交叉功率。两组数据间的小波相干性在四季中均于2-4年及4-8年尺度上表现出显著相关性。结果表明喀拉拉邦的季节性降雨与太阳活动存在关联。研究确定了第14-24太阳周期各季节的太阳活动相位，并识别了降雨过量与不足的年份。观测发现下降相对冬季和季风前季节的过量降雨事件产生影响，而上升相对季风及季风后季节的影响尤为显著。本研究特别考察了交替太阳周期中太阳黑子的不同磁极性，重点关注偶数和奇数周期。发现极端降雨事件在偶数周期的冬季和季风前季节更为频繁，而在奇数周期则多集中于季风和季风后季节。这些发现首次揭示了不同相位对降雨的影响机制，可能为相关研究提供新视角。本研究表明太阳活动与喀拉拉邦极端降水之间存在物理联系，这有望提升降水事件的可预测性。