A Census of the 1993–2016 Complex Mesoscale Eddy Processes in the South China Sea

Jiawei Yi,Huimeng Wang,Yong Sun,Yunyan Du,Fuyuan Liang

doi:10.3390/w11061208

Abstract

Mesoscale eddy process with at least one splitting and/or merging event can be defined as either a complex process or a simple process. Investigation of the difference between these two categories could provide new insights into how different factors, such as the seabed topography, Kuroshio intrusion, and winds, affect the origin, migration, and decay of the mesoscale eddies. This study compared the characteristics of the complex against the simple eddy processes in the South China Sea (SCS) from 1993 to 2016. We comprehensively analyzed the eddy processes with regards to their characteristic points, trajectories, and networks. The simple and complex processes share many similarities but do show significantly different behaviors. Both the simple and complex processes mainly start from the eastern SCS. However, the complex processes mainly vanish in the western SCS whereas the simple processes disappear almost everywhere across the SCS. The complex processes last longer and migrate more than the simple processes. Lastly, the complex processes mainly move westward within the community. The complex processes can be further categorized into complex anticyclonic and cyclonic eddy processes. Spatially, the splitting and merging events mainly occur in the southwest of Taiwan, northwest of the Luzon Island, and the southeast of Vietnam. Temporally, the merging and splitting events mainly occur in the fall. The interaction among the communities reveals the different migration patterns of the complex anticyclonic and cyclonic eddy processes in the SCS.

Highlights

Mesoscale eddies are a common dynamic phenomenon in the ocean, which is constantly moving around and changing with respect to their geometric and thematic characteristics
Our study shows that the regions in the South China Sea (SCS) with significant splitting and merging events witness the significant formation of eddies
This study shows the west of Luzon Island probably is an ideal place for scientists to model the relationship between the eddy splitting activities and the topography, which, obviously is not the only factor leading to eddy splitting and merging

Summary

Introduction

Mesoscale eddies are a common dynamic phenomenon in the ocean, which is constantly moving around and changing with respect to their geometric and thematic characteristics. Water 2019, 11, 1208 eddies [7,8,9], to examine eddies statistical characteristics [10,11,12,13,14,15] and the driving mechanisms behind them [16,17,18,19], and to study the influences of eddies on current circulation [2,20,21], oceanic ecology, and biogeochemical processes [5,22]. Mesoscale eddies are very common and active in the South China Sea (SCS), which is a marginal sea of the Pacific Ocean and the largest semi-enclosed sea in the tropics. Polar eddy current heat transfer was found in summer in the east of Vietnam. In the western Luzon Strait, a large equatorial heat transfer was found in winter

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