Mean properties of mesoscale eddies in the Kuroshio recirculation region

• Published in: Chinese journal of oceanology and limnology Vol. 32; no. 3; pp. 681 - 702
• Main Author: 马利斌 王强
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.05.2014; Springer Nature B.V
• Subjects: Correlation analysis; Current rings; data collection; Earth and Environmental Science; Earth Sciences; Eddies; Eddy currents; Evolution; Marine; Mesoscale convective complexes; Mesoscale eddies; Nonlinear systems; Nonlinearity; Ocean circulation; Ocean temperature; Oceanography; Physics; Propagation; Sea surface; Sea surface temperature; Seasonal variation; Seasonal variations; Skewed distributions; Spatial distribution; Surface temperature; Vertical shear; wind; Wind stress; Wind stress curl; 中尺度涡; 回流区; 平均半径; 平均寿命; 年际时间尺度; 性能; 涡流检测; 黑潮; INW, Pacific, Kuroshio Current; spatial distributions; mesoscale eddies; potential factors; temporal variations
• ISSN: 0254-4059; 2096-5508; 1993-5005; 2523-3521
• DOI: 10.1007/s00343-014-3029-2

Using a 19-year altimetric dataset, the mean properties and spatiotemporal variations of eddies in the Kuroshio recirculation region are examined. A total of 2 001 cyclonic tracks and 1 847 anticyclonic tracks were identified using a geometry-based eddy detection method. The mean radius was 57 km for cyclonic eddies and was 61 km for anticyclonic eddies, respectively, and the mean lifetime was about 10 weeks for both type eddies. There were asymmetric spatial distributions for eddy generation and eddy termination, which were domain-dependent. Mean eddy generation rates were 2.0 per week for cyclonic eddies and were 1.9 per week for anticyclonic eddies. Both type eddies tended to deform during their lifetime and had different propagation characteristics, which mainly propagated westward and southwestward with velocities 4.0-9.9 cm/s, in the Kuroshio recirculation region. Further discussion illustrates that the eddy westward speed maybe influenced by the combined effect of vertical shear of horizontal currents and nonlinearity of eddy. To better understand the evolution of eddy tracks, a total of 134 long-lived tracks （lifetime 〉20 weeks） were examined. Comparison between short-span eddies （lifetime 〉4 weeks and 〈20 weeks） and long-lived eddies is also conducted and the result shows that the short-span and long-lived eddies have similar time evolution. Finally, eddy seasonal variations and interannual changes are discussed. Correlation analysis shows that eddy activity is sensitive to the wind stress curl and meridional gradient of sea surface temperature on interannual timescales. Besides, the strength and orientation of background flows also have impacts on the eddy genesis.