Characteristics of ocean mesoscale eddies in the Agulhas and Tasman Leakage regions from two eddy datasets

Abstract

Mesoscale eddies play an essential role in the freshwater transport, ocean circulation and climate. Although there is no completely objective eddy dataset, observations can better reproduce the eddies in the ocean as data resolution is improved and eddy detection methods are developed to some extent. This study uses satellite altimeter data and compares the Mesoscale Eddy Trajectory Atlas Product (META) with the Global Ocean Mesoscale Eddy Atmospheric-Oceanic-Biological Interaction Observational Dataset (GOMEAD) to analyze the mesoscale eddy characteristics in the oceanic pathways in the Agulhas Leakage (AL) region at the intersection of the Indian and Atlantic Oceans, and the Tasman Leakage (TL) region between the Indian and Pacific Oceans. Here we show that, the META dataset is more applicable for the detection of small-radius eddies, but this product increases the risk of over-detection. The GOMEAD dataset offers precise eddy boundaries and is useful for identifying large diameter eddies. The characteristics of eddies in the AL and TL regions are analyzed, and the results indicate that GOMEAD is more suited for eddy detection and analysis in the AL, while the META dataset is better suited for studies of mesoscale eddies of the TL region. Choosing the appropriate dataset is important for understanding the role of mesoscale eddies of different areas in a changing climate.