Effect of Regional Anthropogenic Aerosols on Tropical Cyclone Frequency of Occurrence

Previous studies have highlighted the distinct impacts of anthropogenic aerosols from the Western and Eastern Hemispheres on past multi-decadal changes in tropical cyclone frequency of occurrence (TCF). However, the detailed effect of subregional aerosol variations remained unclear. Using idealized simulations with a dynamical climate model, this study reveals that reduced aerosol emissions from Europe and the U.S. since 1980 may have equally contributed to increased TCF over the North Atlantic, with Europe playing a major role in the decreased TCF in the South Indian Ocean and the U.S. contributing to the decrease in TCF in the South Pacific. Additionally, increased aerosol emissions from India since 1980 may have played a major role in decreasing TCF over the western North Pacific compared to increased emissions from China. TCFs are projected to decrease for most global tropics toward the end of this century due to the dominant effect of increasing greenhouse gases.