Contributions of atmospheric forcing and chaotic ocean variability to regional sea level trends over 1993‐2015

W. Llovel (1) , Thierry Penduff (2) , Benoit Meyssignac (1) , Jean‐marc Molines (2) , Laurent Terray (3) , Laurent Bessières (3) , Bernard Barnier (2)

1 LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
2 IGE - Institut des Géosciences de l’Environnement
3 CERFACS - Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique

A global ¼° ocean/sea-ice 50-member ensemble simulation is analyzed to disentangle the imprints of the atmospheric forcing and the chaotic ocean variability on regional sea level trends over the satellite altimetry period. We find that the chaotic ocean variability may mask atmospherically forced regional sea level trends over 38% of the global ocean area from 1993 to 2015, and over 47% of this area from 2005 to 2015. These regions are located in the western boundary currents, in the Southern Ocean and in the subtropical gyres. While these results do not question the anthropogenic origin of global mean sea level rise, they give new insights into the intrinsically oceanic versus atmospheric forcing of regional sea level trends and provide new constraints on the measurement time required to attribute regional sea level trends to the atmospheric forcing or to climate change.

Domaines: Océan, Atmosphère; Océanographie

W. Llovel, Thierry Penduff, Benoit Meyssignac, Jean‐marc Molines, Laurent Terray, et al.. Contributions of atmospheric forcing and chaotic ocean variability to regional sea level trends over 1993‐2015. Geophysical Research Letters, 2018, 45 (24), pp.13,405-13,413. ⟨10.1029/2018gl080838⟩. ⟨hal-02003015⟩