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UP: Fachverband Umweltphysik
UP 2: Volcanic Effects on Atmosphere and Climate
UP 2.5: Talk
Wednesday, March 22, 2023, 12:15–12:30, MOL/0213
Impact of a strong volcanic eruption on the summer middle atmosphere in UA-ICON simulations — •Sandra Wallis1, Hauke Schmidt2, and Christian von Savigny1 — 1University of Greifswald, Greifswald, Germany — 2Max Planck Institute for Meteorology, Hamburg, Germany
Explosive tropical volcanic eruptions are able to inject large amounts of sulfur dioxide into the stratosphere. Sulfur dioxide mostly converts to sulfate aerosols that can increase the temperature of the lower stratosphere and subsequently alter the stratospheric circulation. This was directly observed after the strong Pinatubo eruption in 1991. The impact on the mesosphere is less well understood, mainly because of a lack of strong eruptions during the satellite era and sparse observations of the middle atmosphere before. Few measurements, however, hint to an increase in mesospheric temperatures after the Pinatubo eruptions. We investigate dynamical mechanisms that could explain such observations by simulating the response of the middle atmosphere to an idealized tropical eruption that emitted twice as much sulfur dioxide as the Pinatubo in 1991 using the upper-atmospheric icosahedral non-hydrostatic (UA-ICON) model. We focus on the first austral summer after the eruption and find a significant warming of the polar summer mesopause of up to 15-21 K. Our study indicates that this mesospheric warming is mainly due to vertical coupling through wave-mean flow interaction in the summer hemisphere and potentially enhanced by interhemispheric coupling (between the winter stratosphere and the summer mesosphere).