EGU24-9179, updated on 08 Mar 2024
https://doi.org/10.5194/egusphere-egu24-9179
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Post-eruption tropical water vapour transport: Pinatubo and Hunga Tonga-Hunga Ha’apai

Xin Zhou1,2, Wenhui Zhang1, Graham Mann2, Wuhu Feng2,3, Sandip Dhomse2,4, and Martyn Chipperfield2,4
Xin Zhou et al.
  • 1School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, China
  • 2School of Earth and Environment, University of Leeds, Leeds, UK
  • 3National Centre for Atmospheric Science, University of Leeds, Leeds, UK
  • 4National Centre for Earth Observation, University of Leeds, Leeds, UK

The June 1991 Pinatubo and January 2022 Hunga Tonga-Hunga Ha’apai (HTHH) are the two most explosive tropical volcanic eruptions in 30 years. The two, one with high sulfur dioxide (SO2) emission and the other high water vapour (H2O) emission, provide two different paradigm cases to understand the post-eruption tropical transport. Here we use the VolMIP short-term climate-response experiments with the UK Earth System Model (UKESM1) to explore the post-eruption tropical H2O transport after a high-SO2 case.

Aerosol-absorptive heating causes peak SWV increases of 17% (~1 ppmv) and 10% (0.5 ppmv) at 100 hPa and 50 hPa, at ~18 months and ~23 months post-eruption, respectively. The main SWV increase occurs only after the descending aerosol heating reaches the tropopause, suggesting a key role for aerosol microphysical processes (sedimentation rate). This increase is strongly modulated by ENSO variability. With a consistent biased Quai-Biannual Oscillation (QBO) towards the westerly phase, tropical upwelling under different ENSO conditions strongly mediates this effect.

We will also discuss the observed tropical H2O entry after HTHH eruption. With a triple-dip La Niña background and the strong H2O-induced cooling in the lower stratosphere, the tropical H2O transport through 2022/23 is dominated by the volcanic forcing and the sea surface temperature. An up-to-date observation from satellite data is used for analysing this unique HTHH volcanic forcing, while future modelling is needed for a tangible impact.

How to cite: Zhou, X., Zhang, W., Mann, G., Feng, W., Dhomse, S., and Chipperfield, M.: Post-eruption tropical water vapour transport: Pinatubo and Hunga Tonga-Hunga Ha’apai, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9179, https://doi.org/10.5194/egusphere-egu24-9179, 2024.