Interannual eddy variability in the eastern Ryukyu Island chain

Frontiers in Marine Science

Marine Science

Hirohiko Nakamura¹  Shin’ichiro Kako²  Zhen-Long Zhang³  Xiao-Hua Zhu⁴ 

[1] Faculty of Fisheries, Kagoshima University, Kagoshima, Japan;Graduate School of Science and Engineering, Kagoshima University, Kagoshima, Japan;Pan-Okhotsk Research Center, Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan;State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China;Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Yat-sen University, Zhuhai, China;School of Oceanography, Shanghai Jiao Tong University, Shanghai, China;

关键词: mesoscale eddy;    interannual variability;    Ryukyu Current;    baroclinic instability;    North Equatorial Current;   

DOI  :  10.3389/fmars.2023.1242294

 received in 2023-06-19, accepted in 2023-08-18,  发布年份 2023

来源: Frontiers

【 摘 要 】

Interannual eddy variability in the eastern Ryukyu Island chain (RIC) was analyzed based on eddy trajectories and assimilation data. Analysis of the eddy trajectory data suggested a predominance of eddies originating near the study area. The occurrence frequency of eddies has interannual variability, but it demonstrates a different tendency with eddy kinetic energy (EKE): few eddies appear when EKE is high; however, they are strong with fast rotation speeds and increase in size. The EKE variability was correlated with the baroclinic conversion rates, suggesting a vital role of baroclinic instability in the study area. Baroclinic instability was found to be affected by the North Equatorial Current (NEC), during which more NEC water entered the eastern RIC, intensifying the vertical velocity shear between the upper and lower oceans. Consequently, baroclinic instability in the study area was enhanced.

【 授权许可】

Unknown   
Copyright © 2023 Zhang, Nakamura, Kako and Zhu