Major migration corridors of mesoscale ocean eddies in the South China Sea from 1992 to 2012

Abstract

It has become a routine to automatically identify mesoscale ocean eddies in the world's oceans and reconstruct their trajectories from remote sensing data. However, the major migration pathways along which eddies mainly propagate are not clear, particularly in the South China Sea (SCS). This study utilized a trajectory partition-and-group method to quantitatively measure and group trajectories of eddies in the SCS from 1992 to 2012 to extract their major migration corridors. The trajectories were first simplified into segments using the minimum description length (MDL) principle, their origin and destination (OD) points, and their trajectory partitions (TP) between two consecutive tracking times, respectively. The MDL-, OD-, and TP-based segments were then respectively grouped into clusters using the density-based spatial clustering of applications with noise (DBSCAN) algorithm. Representative trajectories, i.e., the major migration corridors, were then extracted from different clusters. Results show that the MDL-based corridors are the most tenable in revealing the migration corridors of eddies in the SCS. The major MDL-based migration corridors of both anticyclonic and cyclonic eddy in the SCS mainly extend westward and show a meridional propagation toward the equator. The different major migration corridors in the northern, central, and southern SCS could be attributed to the various influences of seabed topography and/or background currents in these regions.