Volcanic eruptions and their effects on soi, sst and indian summer monsoon rainfall

Recent studies have pointed out the modification of Climate by aerosols released in the stratosphere by strong volcanic eruptions. The values of percentage departures of rainfall for India as a whole for each monsoon season (June-September) and volcanoes,having volcanic explosivity index(VEI)4 or more, for a period of 1010 years(1901-2009), are investigated to examine the effects of the eruptions on the rainfall activity over India, An attempt has also been made in the present study to investigate the effects of volcanic eruptions on southern oscillation index(SOI) and sea surface temperatures(SST). The present study has suggested deficient rainfall during first and the year following year of volcanic eruption in 17 out of 22 years and -Ve SOI in 14 out of 22 years in Indian summer monsoon. The present study also suggested an increase in sea surface temperatures in 12 out of 22 years following the volcanic eruption.