The role of Solar Activity in shaping Precipitation Extremes: A Regional Exploration in Kerala, India

TL;DR

This study investigates how solar activity influences extreme precipitation events in Kerala, India, revealing significant correlations during specific seasons and suggesting potential for predictive modeling based on solar indices.

Contribution

It provides a regional analysis linking solar activity to rainfall extremes in Kerala, highlighting seasonal variations and regional differences in solar influence.

Findings

Strong correlation between solar activity and winter, monsoon rainfall

High solar activity periods align with excess or deficient rainfall years

Regional differences in solar influence within Kerala

Abstract

There has been global attention focused on extreme climatic changes. The purpose of this paper is to explore the response of extreme precipitation events to solar activity, over Kerala, India. The three solar indices - sunspot number, F10.7 index, and cosmic ray intensity - are examined, and their relationship to rainfall is examined during a 57-year period (1965 - 2021), starting with Solar Cycle 20. Both solar and rainfall data are considered on an annual scale as well as on a seasonal scale by dividing them into winter, pre-monsoon, monsoon, and post-monsoon seasons. The solar indices are used to calculate correlation coefficients with seasonal rainfall. Through correlation analysis, it is found that the precipitation in Kerala is correlated with the sunspot activity, but with different significance. When solar activity is high, the winter and monsoon seasons exhibit strong correlations with high significance. The solar influence at the regional level is also studied. The central and southern parts of Kerala appear to be influenced by the Sun during periods of high activity. The years with excess and deficiency of rainfall are calculated and compared with the solar indices. It was observed that the years with excessive and insufficient rainfall coincide with the years when the solar activity is at its highest or minimum. It is suggested that there is a physical link and a way to predict extreme rainfall events in Kerala based on the association between solar activity and those events.