Influence of solar activity on the rainfall over India ILWS Workshop 2006

Abstract

We use 130 years of Indian rainfall for studying correlative effects due to solar cycle and activity phenomena, viz., the occurrences of sunspot activity and the irradiance variations. Among all the seasons of the Indian rainfall activity, the Indian Monsoon rainfall, with a high significance, is positively correlated with the sunspot and irradiance activities. We subject the Indian Monsoon rainfall and the sunspot occurrence activities with FFT and wavelet analysis. It is found that both the activities have a common periodicity of 22 year indicating that the solar cycle and activity phenomena strongly influence the rainfall activity. We conjecture a possible physical connection between the occurrence of the rainfall variability and the sunspot activity and, the flux of galactic cosmic rays. Some of the negative correlations from the analysis of cycle-to-cycle variations are interpreted as due aerosol effects due to either intermittent volcanic eruptions or due to intrusion of interstellar dust particles in the earth’s atmosphere.