Project funded by ANR/PRACE (2014-2018). Principal Investigator: Thierry Penduff

Most of the analyses of the OCCIPUT ensemble simulations have been performed in the framework of the PIRATE project

Ocean Chaos - Impacts, Structures, predicability

Characterizing the stochastic nature of the ocean variability on interannual-to-decadal timescales in a large ensemble of 1/4º ocean/sea-ice hindcasts.

Turbulent ocean models spontaneously generate a chaotic variability up to multi­decadal/basin scales. How this low­-frequency chaos impacts climate-relevant oceanic indices is an important unsettled question. To separate this chaos from the atmospherically-forced response, MEOM and CERFACS have performed a pioneering 50-member ensemble of 1/4° global ocean/sea-ice simulations (1960-2015), starting from perturbed initial conditions then driven by the same atmospheric forcing with time. The results reveal the importance of the oceanic chaos up to large spatio-temporal scales and its modulation by the atmosphere, and this raises new issues about the detection/attribution of climate change in the ocean and the potential impact of this low-frequency chaos on the atmosphere.


Figure : The OCCIPUT ensemble experiment:


OCCIPUT documents and presentations:

  • OCCIPUT seminar given at Ecole de Physique des Houches, August 2017 [video]

  • OCCIPUT presentation given at the GMMC workshop, June 2016 [pdf] (10 Mo).

  • OCCIPUT ANR summary [here]


Thierry Penduff (P.I.).


The outputs of the OCCIPUT ensemble simulation are available upon request. Please contact Thierry Penduff (P.I.).

Project participants:

  • MEOM/LGGE, Grenoble, France.
  • CERFACS, Toulouse, France.