黑潮延伸体海域次中尺度过程的季节变化研究  

Seasonal variability of submesoscale flows in the Kuroshio Extension

作　　者：罗士浩 经志友[1] 闫桐[1] 郑瑞玺 曹海锦[3] 齐义泉 LUO Shihao;JING Zhiyou;YAN Tong;ZHENG Ruixi;CAO Haijin;QI Yiquan(State Key Laboratory of Tropical Oceanography(South China Sea Institute of Oceanology,Chinese Academy of Sciences),Guangzhou 510301,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Oceanography,Hohai University,Nanjing,210098,China)

机构地区：[1]热带海洋环境国家重点实验室(中国科学院南海海洋研究所),广东广州510301 [2]中国科学院大学,北京100049 [3]河海大学海洋学院,江苏南京210098

出　　处：《热带海洋学报》2021年第1期1-11,共11页Journal of Tropical Oceanography

基　　金：中国科学院基础前沿科学研究计划原始创新项目(ZDBS-LY-DQC011);国家自然科学基金项目(92058201、41776040);中国科学院南海生态环境工程创新研究院自主部署项目(ISEE2018PY05);青岛海洋科学与技术试点国家实验室OCFL功能实验室开放课题(OCFL-201804);广州市科学研究计划(201904010420)。

摘　　要：近年来的现场观测和理论研究发现,次中尺度现象广泛存在于上层海洋,其产生与锋生作用及混合层斜压不稳定存在密切联系。本文利用高分辨率的数值模拟结果并结合动力学及能量诊断分析,对黑潮延伸体海域次中尺度过程的季节变化进行了探讨。探讨结果表明,黑潮延伸体海域次中尺度过程具有冬季最强,春季和秋季次之,夏季最弱的显著季节变化特征。基于冬、夏季次中尺度能量源的诊断可以看到,这些季节变化特征主要与上层海洋的斜压不稳定和锋生作用有关。冬季,黑潮延伸体海域的中尺度能量较弱,但次中尺度过程在季节尺度上表现最为活跃,这主要与混合层斜压不稳定的作用有关;夏季,黑潮延伸体海域的混合层较浅,次中尺度过程较弱,但中尺度涡旋活跃,中尺度流场变形引起的锋生作用对夏季次中尺度现象的产生具有重要影响。在次中尺度能量的季节变化方面,冬季次中尺度过程从中尺度过程汲取能量的速率远高于夏季,这是冬季次中尺度过程比夏季更为活跃的主要原因。本文研究结果有助于加深对黑潮延伸体海域次中尺度过程季节性变化及其动力机制的理解。Recent field observations and theoretical analysis have revealed that submesoscale activities are ubiquitous in the upper ocean, and that their formation is closely related to frontogenesis and mixed layer instability. Based on high-resolution numerical simulations and diagnostic analysis, we investigate the seasonal variability of submesoscale activities in the upper ocean of the Kuroshio Extension. The results suggest that the submesoscale behaviors in the Kuroshio Extension have significant seasonal variation. Although the mesoscale eddy energy of the Kuroshio Extension is weak in winter, the submesoscale activities are the most active on the seasonal scale, which is likely due to the contribution of the mixed layer baroclinic instabilities in the upper ocean. The mixed layer is shallow in summer with weak submesoscale activities, but the mesoscale eddies are active. The diagnosis of frontal tendency suggests that the frontogenesis caused by the deformation of mesoscale flows be the main contributor to the submesoscale activities in summer. Also, the energy transformation from mesoscale to submesoscale has significant seasonal variation with the conversion rates of available potential energy and kinetic energy in winter much higher than those in summer, which contributes to richer submesoscale activities in winter than in summer. These results can improve our understanding of the seasonal variation of submesoscale activities and their dynamical mechanisms in the Kuroshio Extension.

关 键 词：黑潮延伸体 次中尺度过程 季节变化 锋生作用 

分 类 号：P731.27[天文地球—海洋科学]