Impact of a strong volcanic eruption on the summer middle atmosphere in UA-ICON simulations.

Autor: Wallis, Sandra, Schmidt, Hauke, Savigny, Christian von
Předmět:
Zdroj: EGUsphere; 1/6/2023, p1-20, 20p
Abstrakt: Explosive volcanic eruptions emitting large amounts of sulfur can alter the temperature of the lower stratosphere and change the circulation of the middle atmosphere. The dynamical response of the stratosphere to strong volcanic eruptions has been the subject of numerous studies. The impact of volcanic eruptions on the mesosphere is less well understood because of a lack of large eruptions in the satellite era and only sparse observations before that period. Nevertheless, some measurements indicated an increase in mesospheric mid-latitude temperatures after the 1991 Pinatubo eruption. The aim of this study is to uncover potential dynamical mechanisms that may lead to such a mesospheric temperature response. We use the upper-atmospheric icosahedral non-hydrostatic (UA-ICON) model to simulate the atmospheric response to an idealized strong volcanic injection of 20 Tg S into the stratosphere (about twice as much as the eminent 1991 Pinatubo eruption). The simulation shows a significant warming of the polar summer mesospause of up to 15–21~K in the first November after the eruption. We argue that this is mainly due to intrahemispheric dynamical coupling in the summer hemisphere and potentially enhanced by interhemispheric coupling with the winter stratosphere. This study will focus on the first austral summer after the eruption, because mesospheric temperature anomalies are especially relevant for the properties of noctilucent clouds whose season peaks around January in the southern hemisphere. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index