Response of stratospheric water vapor and ozone to the unusual timing of El Niño and the QBO disruption in 2015–2016

Mohamadou Diallo (1) , Martin Riese (2) , Thomas Birner (3) , Paul Konopka (2) , Rolf Müller (2) , Michaela Hegglin (4) , Michelle Santee (5) , Mark Baldwin (6) , Bernard Legras (7) , Félix Ploeger (2)

1 CIRDES - Centre international de recherche-développement sur l'élevage en zone sub-humide
2 IEK-7 - Institut für Energie- und Klimaforschung - Stratosphäre
3 LMU - Ludwig Maximilian University [Munich] = Ludwig Maximilians Universität München
4 Department of Meteorology [Reading]
5 JPL - Jet Propulsion Laboratory
6 EMPS - College of Engineering, Mathematics and Physical Sciences [Exeter]
7 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)

The stratospheric circulation determines the transport and lifetime of key trace gases in a changing climate, including water vapor and ozone, which radiatively impact surface climate. The unusually warm El Niño-Southern Oscillation (ENSO) event aligned with a disrupted Quasi-Biennial Oscillation (QBO) caused an unprecedented perturbation to this circulation in 2015-2016. Here, we quantify the impact of the alignment of these two phenomena in 2015-2016 on lower stratospheric water vapor and ozone from satellite observations. We show that the warm ENSO event substantially increased water vapor and decreased ozone in the tropical lower stratosphere. The QBO disruption significantly decreased global lower stratospheric water vapor and tropical ozone from early spring to late autumn. Thus, this QBO disruption reversed the lower stratosphere moistening triggered by the alignment of the warm ENSO event with westerly QBO in early boreal winter. Our results suggest that the interplay of ENSO events and QBO phases will be crucial for the distributions of radiatively active trace gases in a changing future climate, when increasing El Niño-like conditions and a decreasing lower stratospheric QBO amplitude are expected .

Domaines: Océan, Atmosphère

Mohamadou Diallo, Martin Riese, Thomas Birner, Paul Konopka, Rolf Müller, et al.. Response of stratospheric water vapor and ozone to the unusual timing of El Niño and the QBO disruption in 2015–2016. Atmospheric Chemistry and Physics, 2018, 18 (17), pp.13055-13073. ⟨10.5194/acp-18-13055-2018⟩. ⟨hal-02377539⟩