The effect of major volcanic eruptions on tropical cyclone activity

In 1982 and 1991 major volcanic eruptions of El Chichón and Mt. Pinatubo resulted in well-known widespread reductions in surface solar insolation. While it is generally understood that over water a decrease in downwelling solar radiation will tend to cool the surface, few studies have actually attempted to explicitly identify the magnitude and spatial pattern of that cooling. Here we use a historical record of stratospheric aerosol optical depth in conjunction with a simple radiative transfer model and an ocean GCM to model the effect of these two eruptions on surface and subsurface temperature anomalies in the tropics. We focus on volcanic aerosol-forced changes in ocean temperature and the spatial structure of those anomalies in the cyclone development regions of the Atlantic, Pacific, and Indian Oceans. We investigate the impact of these stratospheric aerosols on tropical cyclones by estimating local changes in maximum potential intensity and regional circulation patterns that result from the sea surface temperature anomalies.