The role of tropical volcanic eruptions in exacerbating Indian droughts

Large volcanic eruptions have been linked with reductions in ISMR, but the responsible mechanisms remain unclear. Here, using 145-year (1871-2016) records of volcanic eruptions and ISMR, we show that ISMR deficits prevail for two years after moderate and large (VEI>3) tropical volcanic eruptions; this is not the case for extra-tropical eruptions.

Moreover, tropical volcanic eruptions strengthen El Nino and weaken La Nina conditions, further enhancing Indian droughts. Using climate-model simulations of the 2011 Nabro volcanic eruption, we show that eruption induced an El Nino like warming in the central Pacific for two consecutive years due to Kelvin wave dissipation triggered by the eruption. This El Nino like warming in the central Pacific led to a precipitation reduction in the Indian region.