Bjerknessenterets mål er å forstå klima
til nytte for samfunnet.

Seminar talk: The ENSO response to volcanic eruptions

On 13 September Francesco S.R. Pausata will give a seminar talk. He is from University of Quebec in Montreal.

Portrait Francesco Pausata
Francesco S.R. Pausata

Short biography:

PhD at GFI

Post doc at European Commission in Italy

Post doc at Stockholm University

Professor at UQAM



The mechanisms through which volcanic eruptions affect 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. We test these mechanisms through a set of sensitivity experiments 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, and on limited areas of the tropics. 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 play a detectable rules in our simulations. The results of these simulations highlight 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.


Arranged date for the seminar talk: Sep 13, 2021 at 14:15

BCCR lecture room 4020/zoom (hybrid meeting)