324 / 2022-06-30 16:50:39

A Tale of Two Tropical Cyclones Affected by Volcanic Aerosols: Wukong (2018) and Cody (2022)

Tropical Cyclone；,Volcanic Aerosols

The number of tropical cyclones (TCs) over the western North Pacific from June to August 2018 ranks second since the satellite era. Was this related to the continuous eruption of the Kilauea volcano at Hawaii from May to August 2018? The role of volcanic aerosols on tropical cyclogenesis has not yet been clearly understood and remains one of the important factors that impede our understanding on the climatological response of TC activity to volcanic aerosols.

The impacts of volcanic aerosols from the eruption of the Kilauea volcano on the genesis of Typhoon Wukong in 2018 are investigated by numerical simulations with/without aerosol−cloud−radiation interactions. With only aerosol−radiation effect included, the radiative cooling at the low levels and heating above by aerosols induced stable sinking and decreased latent heating in Wukong’s environment. As a result, the sea-level pressure increased in the outer region, enhancing low-level radial inflow, inner-core convection and the release of latent heating, which was conducive to TC genesis. Further including the aerosol−cloud effect shows that the volcanic aerosols in TC circulation could be converted into cloud condensation nuclei, subsequently invigorating peripheral convection. The vigorous peripheral clouds draw more ascending air at the periphery of the storm, thereby weakening the low-level inflow toward the eyewall, which is not favorable for TC genesis. Only the experiments that include both radiation and aerosol−cloud effects of volcanic aerosols can reasonably capture the timing of TC genesis.

TC Cody was very near the volcano Hunga Tonga–Hunga Ha‘apai during the eruption on 15 January 2022. The comparison of the effects of volcanic aerosols between on Cody (2022) and on Wukong (2018) will also be presented on the conference. This study may also have implications for exploring the impact of aerosols on potential changes in the regional and global climatology of TC activities.