EGU2020-2067
https://doi.org/10.5194/egusphere-egu2020-2067
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

ITCZ shift and extratropical teleconnections drive ENSO response to volcanic eruptions

Francesco S.R. Pausata1, Davide Zanchettin2, Christina Karamperidou3, Rodrigo Caballero4, and David S. Battisti5,6
Francesco S.R. Pausata et al.
  • 1Centre ESCER and GEOTOP, Department of Earth and Atmospheric Sciences, University of Quebec in Montreal, Montreal, QC, Canada (pausata.francesco@uqam.ca)
  • 2Department of Environmental Sciences, Informatics and Statistics, University Ca’Foscari of Venice, Mestre, Italy
  • 3Department of Atmospheric Sciences, University of Hawaii at Mānoa, Honolulu, Hawaii, USA
  • 4Department of Meteorology, Stockholm University and Bolin Centre for Climate Research, Stockholm, Sweden
  • 5Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA
  • 6UNI Research, Bergen, Norway

The mechanisms through which volcanic eruptions impact the El Niño-Southern Oscillation (ENSO) state are still controversial. Previous studies have invoked direct radiative forcing, an ocean dynamical thermostat (ODT) mechanism and shifts of the Intertropical Convergence Zone (ITCZ), among others, to explain the ENSO response to tropical eruptions. Here, these mechanisms are tested using ensemble simulations with an Earth System Model in which volcanic aerosols from a Tambora-like eruption are confined either in the Northern or the Southern Hemisphere. We show that the primary drivers of the ENSO response are the shifts of the ITCZ together with extratropical circulation changes, which affect the tropics; the ODT mechanism does not operate in our simulations. Our study highlights the importance of initial conditions in the ENSO response to tropical volcanic eruptions and provides explanations for the predominance of post-eruption El Niño events and for the occasional post-eruption La Niña in observations and reconstructions.

How to cite: Pausata, F. S. R., Zanchettin, D., Karamperidou, C., Caballero, R., and Battisti, D. S.: ITCZ shift and extratropical teleconnections drive ENSO response to volcanic eruptions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2067, https://doi.org/10.5194/egusphere-egu2020-2067, 2020

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