Detection of Mesoscale Eddies through Refined Winding-Angle Method

Abstract

Winding Angle method is the common eddy detection mode  using geometric approach.  It is based on the instantaneous streamlines' geometric properties. But the winding angle method works under the assumption, the mesoscale eddies are circular in shape, which is not the case in real time scenarios. In real time, eddies are elongated ones, as ocean flows are turbulent in nature. This restriction of shape may also result in excess/under detection of eddies. In this paper, a refined winding angle method is proposed, which to a great extent attempts to rectify the drawbacks of the original winding angle method. The experiments of the work are done using Sea Level Anomaly Data in the world’s biggest bay, Bay of Bengal. The results are verified with the data from Argo float. A detailed comparison of the eddies which are detected using the original method and the refined approach points to the observation, that the eddies detected through the refined approach are elongated in shape. The Successful Detection Rate (SDR) and Excessive Detection Rate (EDR) values are high and low respectively for the proposed refined approach.