Tongan Volcanic Eruption Intensifies Tropical Cyclone Cody (2022)

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The aerosol−cloud impacts of the Tongan volcanic eruptions on the nearby tropical cyclone (TC) Cody on January 14∼15, 2022 are investigated by the MODIS satellite and ERA5 reanalysis data. Both the precipitation and intensity of Cody were obviously enhanced after the main blast of the Tongan volcanic eruption on January 15, although the sea surface temperature and vertical wind shear of the environmental wind did not change much according to ERA5 data. The vision that a large amount of volcanic aerosol flowed from the Tongan eruption into the inflow of Cody was captured by the MODIS observations on January 15. The cloud top temperature dropped, and the cloud particle effective radius decreased in Cody from then on, which indicated the occurrence of deep convection. The analyzed results of ERA5 show that convection was strengthened in the periphery of Cody at the beginning of the volcanic eruption at 03:00 UTC on January 15 and later in Cody’s inner core after the main blast at 06:00 UTC on January 15. This could be because of the microphysical process of aerosol−cloud interactions, which inhibited stratiform precipitation, increased vertical velocity and enhanced convective precipitation further. Since the deep convection in the inner core was conducive to the development of Cody, both the total precipitation and intensity of Cody increased after the main blast of the volcanic eruption. The result also suggests that major volcanic eruptions could increase the convective intensity and induce heavy precipitation in a nearby organized convective system (e.g., TC or mesoscale convective systems).