Growth and global persistence of stratospheric sulfate aerosols from the
2022 Hunga Tonga-Hunga Ha'apai volcanic eruption
Abstract
Stratospheric sulfate aerosols play a key role on atmospheric chemistry
and Earth’s radiation budget, but their size distribution, a critical
parameter in climate models, is generally poorly-known. We address such
gap for the 2022 Hunga Tonga-Hunga Ha’apai (HT-HH)
volcanic eruption by exhaustively analyzing a set
of satellite observations together with photometric
ground observations from the worldwide
open-access AERONET network. We document a rapid growth of HT-HH sulfate
aerosols in the days following eruption, faster than observed for other
stratospheric eruptions, likely due to the exceptional hydration of the
stratosphere by this phreatomagmatic eruption. An unusual aerosol fine
mode (peak radius in 0.3-0.5 microns) is identified at
20 stations of the southern hemisphere until May 2023 (time of writing).
Nevertheless, 1.4 years after eruption, HT-HH sulfate aerosols remain
smaller than 1991 Pinatubo particles. Smaller aerosols backscatter more
efficiently visible light and sediment more slowly than larger
particles, implying stronger and longer-lasting negative radiative
forcing.