Effects of Volcanic Aerosols on the Genesis of Tropical Cyclone Wukong (2018)

The short-range impacts of volcanic aerosols from the eruption of the Kilauea volcano on the genesis of tropical cyclone (TC) Wukong in 2018 are investigated by numerical simulations, as distinct from the studies on the aerosol climate effects. The aerosol-radiation and aerosol-cloud effects are isolated through sensitivity experiments. For the aerosol-radiation effect, the radiative cooling at the low levels and heating above by aerosols southeast of Wukong's periphery induce stable sinking and decrease latent heating in the environment far from the storm center. Therefore, the sea-level pressure increases there, enhancing low-level radial inflow to the storm, inner-core convection and the release of latent heat, which is conducive to TC genesis. For the aerosol-cloud effect, volcanic aerosols in storm circulation can be converted into cloud condensation nuclei, invigorating inner-core convection, and subsequently favoring TC genesis. However, the nonlinear effect resulting from the interaction between aerosol-radiation and aerosol-cloud effects is not conducive to TC genesis, because it weakens the aerosol-cloud effect through the deposition of aerosols and also limits the aerosol-radiation effect through the increasing of peripheral convection.