Antarctic Vortex Dehydration in 2023 as a Substantial Removal Pathway for Hunga Tonga‐Hunga Ha'apai Water Vapor

• Published in: Geophysical Research Letters
• Main Authors: Xin Zhou, Sandip S. Dhomse, Wuhu Feng, Graham Mann, Saffron Heddell, Hugh Pumphrey, Brian J. Kerridge, Barry Latter, Richard Siddans, Lucy Ventress, Richard Querel, Penny Smale, Elizabeth Asher, Emrys G. Hall, Slimane Bekki, Martyn P. Chipperfield
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2024
• Subjects: Hunga Tonga‐Hunga Ha'apai eruption; Antarctic dehydration; ozone depletion; stratospheric transport; chemistry transport model; Geophysics. Cosmic physics; QC801-809; Antarctic; Tonga; Midwinter; Antarc*
• Online Access: https://doi.org/10.1029/2023GL107630; https://doaj.org/article/b90fc2dac0624c0eac2deae042809b07

Abstract The January 2022 eruption of Hunga Tonga‐Hunga Ha'apai (HTHH) injected a huge amount (∼150 Tg) of water vapor (H2O) into the stratosphere, along with small amount of SO2. An off‐line 3‐D chemical transport model (CTM) successfully reproduces the spread of the injected H2O through October 2023 as observed by the Microwave Limb Sounder. Dehydration in the 2023 Antarctic polar vortex caused the first substantial (∼20 Tg) removal of HTHH H2O from the stratosphere. The CTM indicates that this process will dominate removal of HTHH H2O for the coming years, giving an overall e‐folding timescale of 4 years; around 25 Tg of the injected H2O is predicted to still remain in the stratosphere by 2030. Following relatively low Antarctic column ozone in midwinter 2023 due to transport effects, additional springtime depletion due to H2O‐related chemistry was small and maximized at the vortex edge (10 DU in column).