An improved scheme of identifying loops using Lagrangian drifters

Although many eddy identification approaches using drifter trajectories have been put forward, few studies have developed algorithms capable of recognizing complex looping structures in trajectories. Therefore, this paper presents a new method, called an improved automated loop-identifying scheme (AILIS), which is based on the ALIS algorithm proposed by Dong (Dong, 2011), to improve problems existing in the drifter trajectory identification methods. On the one hand, the AILIS method enhances threshold setting of distance in ALIS, on the other hand, combined with self-intersection method proposed by Jiaxun [1], it can detect complex looping structure and extract partial eddy trajectories. The results of experiment show that AILIS can get more instantaneous state and movement information of eddies, and provide an important way to obtain physical parameters of eddy.