Significant Contributions of Volcanic Aerosols to Decadal Changes in the Stratospheric Circulation

M. Diallo (1, 2) , F. Ploeger (2) , P. Konopka (3) , T. Birner (4) , R. Müller (2) , M. Riese (2) , H. Garny (5) , B. Legras (1) , E. Ray (6) , Gwenaël Berthet (7) , Fabrice Jégou (7)

1 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
2 IEK-7 - Institut für Energie- und Klimaforschung - Stratosphäre
3 ICG-1 - Institut für Chemie und Dynamik der Geosphäre - Stratosphäre
4 Department of Atmospheric Science [Fort Collins]
5 IPA - DLR Institut für Physik der Atmosphäre
6 ESRL - NOAA Earth System Research Laboratory
7 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

The stratospheric circulation is an important element of climate as it determines the concentration of radiatively active species like water vapor and aerosol above the tropopause. Climate models predict that increasing greenhouse gas levels speed up the stratospheric circulation. However, these results have been challenged by observational estimates of the circulation strength, constituting an uncertainty in current climate simulations. Here, we quantify the effect of volcanic aerosol on the stratospheric circulation focusing on the Mount Pinatubo eruption and discussing further the minor extratropical volcanic eruptions after 2008. We show that the observed pattern of decadal circulation change over the past decades is substantially driven by volcanic aerosol injections. Thus, climate model simulations need to realistically take into account the effect of volcanic eruptions, including the minor eruptions after 2008, for a reliable reproduction of observed stratospheric circulation changes.

Domains: Ocean, Atmosphere; Climatology; Volcanology

M. Diallo, F. Ploeger, P. Konopka, T. Birner, R. Müller, et al.. Significant Contributions of Volcanic Aerosols to Decadal Changes in the Stratospheric Circulation. Geophysical Research Letters, 2017, 44 (20), pp.10,780-10,791. ⟨10.1002/2017GL074662⟩. ⟨insu-01629550v2⟩