CoAuthors

Sophie Cravatte (Institut de Recherche pour le Développement (IRD), France); Alexis Chaigneau (Institut de Recherche pour le Développement (IRD), France); Awnesh Singh (The University of the South Pacific, Fiji); Frederic Marin (Institut de Recherche pour le Développement (IRD), France); Fabien Durand (Institut de Recherche pour le Développement (IRD), France)

The distribution and characteristics of mesoscale eddies in the Southwest Pacific Tropical Ocean are investigated using observations from combined satellite altimetry (Aviso Duacs) and in situ data. An eddy detection algorithm was used to identify and describe the characteristics of the eddies at the surface. Eddy characteristics such as the mean radius, amplitude, EKE, generation and decay locations are determined for eddies with lifetimes longer than 2 weeks. Eddies are mostly generated in the lee of the islands, and decay when encountering the eastern coasts. They were found to have a much shorter lifetime in the northern part of the study region, due to the presence of many small islands and shallow bathymetry there. The mean vertical structure of the eddies was then investigated using Argo floats profiles and currents from a mooring located east of New Caledonia Island. Eddies were shown to be shallow north of 20°S, and to extend deeper towards the south of the study region, impacting the temperature and currents to more than 1000m depth. Cyclonic and anticyclonic eddies have antisymmetric signatures. The results we report here are of particular relevance for the future high-resolution nadir (Sentinel-3) and swath (SWOT) altimetric missions.