Mesospheric temperature and circulation response to the Hunga Tonga-Hunga-Ha'apai volcanic eruption Journal Article uri icon

Overview

abstract

  • The Hunga Tonga Hunga-Ha’apai (HTHH) volcanic eruption on 15 January; 2022 injected water vapor and SO2 into the stratosphere. Several months; after the eruption, significantly stronger westerlies, and a weaker; Brewer-Dobson circulation developed in the stratosphere of the Southern; Hemisphere and were accompanied by unprecedented temperature anomalies; in the stratosphere and mesosphere. In August 2022 the Sounding of the; Atmosphere using Broadband Emission Radiometry (SABER) satellite; instrument observed record-breaking temperature anomalies in the; stratosphere and mesosphere that alternate signs with altitude. Ensemble; simulations carried out with the Whole Atmosphere Community Climate; Model (WACCM6) indicate that the strengthening of the stratospheric; westerlies explains the mesospheric temperature changes. The stronger; westerlies cause stronger westward gravity wave drag in the mesosphere,; accelerating the mesospheric mean meridional circulation. The stronger; mesospheric circulation, in turn, plays a dominant role in driving the; changes in mesospheric temperatures. This study highlights the impact of; large volcanic eruptions on middle atmospheric dynamics and provides; insight into their long-term effects in the mesosphere. On the other; hand, we could not discern a clear mechanism for the observed changes in; stratospheric circulation. In fact, an examination of the WACCM ensemble; reveals that not every member reproduces the large changes observed by; SABER. We conclude that there is a stochastic component to the; stratospheric response to the HTHH eruption.

publication date

  • July 23, 2023

has restriction

  • green

Date in CU Experts

  • August 2, 2023 6:15 AM

Full Author List

  • Yu W; Garcia RR; Yue J; Smith AK; Wang X; Randel WJ; Qiao Z; Zhu Y; Harvey VL; Tilmes S

author count

  • 11

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