A new mononuclear eddy identification method with simple splitting strategies

Abstract

AbstractA new mononuclear eddy identification method based on sea level anomaly (SLA) data was developed and described in this study. To solve the multinuclear eddy problem, we employed two strategies to split the eddies into individual eddies: the closest angle and the closest distance strategies. Each strategy produces an eddy with only one SLA extremum. The splitting procedure is based on these strategies. No artificial threshold is needed with these strategies, but a threshold for strategy choice is required. The splitting strategies are adaptable to various identification methods. The examples indicate that the splitting procedure clearly captures the mixing of eddies. When applied to the global ocean, the proposed method obtained similar and more reasonable results. The splitting procedure is linear without any iteration; thus, it is very fast (the time complexity is O(N), where N is the number of multinuclear eddy pixels). In statistics, the proposed method can identify approximately 30–40% more eddies than the multinuclear eddy method. AcknowledgementsWe thank the three anonymous reviewers for their constructive suggestions. We also thank Dr. Chi Xu for his help at the start of this project. We thank AVISO for the SLA data.FundingThis work was supported by the National Basic Research Program of China [grant number 2013CB430301], [grant number 2013CB430303]; the National Foundation of Natural Science [grant number 41376017], [grant number 41276025]; the Open Fund of the State Key Laboratory of Satellite Ocean Environment Dynamics [grant number SOED1209].