CoAuthors

Rémi Laxenaire (Laboratoire de Météorologie Dynamique, Paris / LACy, Laboratoire de L’Atmosphère et des Cyclones, UMR 8105 CNRS, Université de La Réunion, Météo-France, Saint-Denis, France); Sabrina Speich (Laboratoire de Météorologie Dynamique, LMD-IPSL,Ecole Normale Supérieure ENS-PSL,Paris, France)

In this study, we investigate mesoscale eddies in the Global Ocean with the help of TOEddies Atlas (Laxenaire et al., 2018). Applied on satellite observations (AVISO/DUACS) of Absolute Dynamic Topography (ADT), TOEddies provides daily information on eddy dynamical characteristics (size,intensity etc.) over a 27 year period (1993-2020) as well as identifies complex eddy-eddy interactions. A statistical description of the mean eddy characteristics, their spatial distributions of eddy occurrences (generation, disappearance and merging/splitting) is firstly provided. Then, a comparative analysis between existing global eddy datasets (Chelton et.al 2011, Tian et.al 2019) is performed. Among the years of observations, several long-lived and coherent mesoscale eddies stand out with lifetimes that exceed 1.5 years. Yet, we find that only a small fraction of them is comparable among datasets while their dynamical characteristics could also substantially differ. Thanks to TOEddies that identifies the multiple merging and splitting events that a single eddy may experience, a complex eddy network is created that reshapes the current view of a unique trajectory associated with one single eddy and allows for an original assessment of the mean eddy pathways. Moreover, eddy detection from altimetry is combined with 20 years of Argo profiling floats in-situ measurements (2000-2020), providing additional information on vertical structure of eddies. An index to identify surface versus subsurface-intensified eddies is used, allowing us to further explore their role in the global ocean circulation as long lasting coherent structures.