Quantifying uncertainties on regional sea level change induced by multidecadal intrinsic oceanic variability

Thierry Penduff (CNRS - IGE, France)

CoAuthors

Guillaume Sérazin (LEGOS, France); Benoit Meyssignac (CNES - LEGOS, France); Laurent Terray (CERFACS, France); Bernard Barnier (CNRS - IGE, France); Jean-Marc Molines (CNRS - IGE, France)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Science II: Large Scale Ocean Circulation Variability and Change

Presentation type: Type Poster

A global eddy-permitting (1/4° resolution) ocean general circulation model, driven during 327 years by a repeated climatological atmospheric forcing, is shown to spontaneously generate a strong chaotic Intrinsic Oceanic Variability (IOV) which reaches multi-decadal timescales.
In eddy-active regions, the sea-level imprint of this multi-decadal nonlinearly-driven “noise” is substantial, weakly autocorrelated, and is comparable to (and may clearly exceed) the corresponding imprint of Internal Climate Variability (ICV) produced by CMIP5 coupled climate models, whose laminar ocean components strongly underestimate the IOV.
Deriving sea-level trends from finite-length time series in eddy-active regions yields uncertainties induced by this ocean-driven multi-decadal IOV, which are of the same order of magnitude as those due to the coupled ICV.
These results, obtained in the framework of the past CHAOCEAN and current PIRATE OST-ST projects, raise issues about the detection and attribution of sea-level changes in certain regions from the relatively short existing altimeter archive, and from certain tide gauge records.

 

Poster show times:

RoomStart DateEnd Date
Concerto Ballroom Thu, Oct 26 2017,14:00 Thu, Oct 26 2017,18:00
Thierry Penduff
CNRS - IGE
France
Thierry.Penduff@cnrs.fr