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22.05.2023: online Ocean Circulation and Climate Dynamics Colloquium
Dr. Jérôme Vialard, Laboratoire d'Océanographie, Sorbonne Université, Paris, France: "Atmospheric nonlinearities and ENSO & CLIVAR working group on ENSO conceptual models"
- online only-
When? Monday, 22 May 2023 at 11 am
Where? zoom https://geomar-de.zoom.us/j/82371599648?pwd=d1JZbU14QUZXd25RTVhPenVWemkwUT09
Meeting ID: 823 7159 9648
Passcode: 179282
Abstract:
In the first part of this talk, I will present recent work on the role of atmospheric nonlinearities for ENSO. ENSO warm (El Niño) and cold (La Niña) phases are not perfectly symmetric, with differences in amplitude (stronger El Niño), spatial pattern (El Niño shifted east) and phase transitions (more systematic for El Niño -> La Niña). Past studies have invoked either oceanic or atmospheric nonlinearities to explain those asymmetries. In this work, we use Atmospheric and Oceanic General Circulation Model experiments to show that atmospheric nonlinearities linked to tropical convection play a key role in ENSO amplitude, pattern and phase transition asymmetries.
In the second part of this talk, I will present activities within the CLIVAR ENSO conceptual model working group. The recharge oscillator (RO) is a surprisingly simple conceptual model of ENSO, that can reproduce most of its properties (amplitude, seasonality, asymmetries, spectrum, predictability). The working group is currently writing a review paper on the RO, and working on a series of RO-based online course. I will present those activities, the RO itself, and future prospects for RO-based research on ENSO hot topics.
