南海上层海洋次中尺度过程空间差异和季节变化特征  

Spatial and seasonal differences of the upper-ocean submesoscale processes in the South China Sea

作　　者：杨潇霄 曹海锦 经志友[2] YANG Xiaoxiao;CAO Haijin;JING Zhiyou(College of Oceanography,Hohai University,Nanjing 210024,China;State Key Laboratory of Tropical Oceanography(South China Sea Institute of Oceanology,Chinese Academy of Sciences),Guangzhou 510301,China)

机构地区：[1]河海大学海洋学院,江苏南京210024 [2]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

出　　处：《热带海洋学报》2021年第5期10-24,共15页Journal of Tropical Oceanography

基　　金：国家重点研发计划项目(2017YFA0604104);热带海洋环境国家重点实验室(中科院南海海洋研究所)开放课题(LTO1907);中国博士后基金(2018M642148);江苏省博士后科研资助计划项目(2018K149C);国家自然科学基金(41776040);青岛海洋科学与技术试点国家实验室海洋动力与气候功能实验室开放课题(OCFL-201804)。

摘　　要：南海是西太平洋最大的边缘海,由于受季风影响显著以及北部海域的黑潮入侵,其动力环境复杂多变,次中尺度过程丰富,且在空间上和时间上存在多变性。文章基于高分辨率数值模式的结果,通过对次中尺度动力参数的分析,对比讨论了南海北部、中部、西部和南部海域4个典型子区域上层海洋次中尺度过程的空间差异、季节变化、影响深度、影响因素等问题。研究发现各区域季节性变化特征和机制有所不同:北部海域受冬季风和黑潮入侵影响,冬季次中尺度的混合层不稳定较强;中部海域同样表现为“冬强夏弱”;西部海域受夏季风影响显著,夏季次中尺度过程更为活跃;而南部海域主要受岛屿地形影响较大,容易产生地形尾涡,季节性特征不明显。统计分析表明,次中尺度过程往往表现出强正相对涡度与高应变特征,在表层更容易出现负位涡,流体稳定性较差。此外,文章从能量学角度对次中尺度过程的主要能量来源、控制因素等进行了讨论。The South China Sea(SCS)is the largest marginal sea in the western Pacific Ocean.Due to the significant monsoons and the impact of the Kuroshio intrusion via the Luzon Strait,the local dynamic environment is complicated.Thus,the submesoscale behaviors in the SCS show clear spatial and temporal differences.In this paper,based on the outputs of a high-resolution numerical model,we examine the spatial and seasonal differences of submesoscale processes,influence depth and possible influencing factors in different sub-regions(the northern SCS,the central SCS basin,the western SCS,and the southern SCS).We find that the seasonal variation and mechanisms in each region is unique:The northern part is affected by the winter monsoon and the intrusion of the Kuroshio obviously,so that the mixed layer instability(MSI)is strong;and the submesoscale processes(SMPs)are active in winter.The SMPs in the central basin also shows stronger in winter and weaker in summer.The enhanced summer SMPs in the western SCS are attributed to the summer monsoon.The multi-island topography in the southern SCS generates great submesoscale wake eddies,which do not show significant seasonality.Statistical analysis shows that submesoscale processes tend to be associated with strong positive relative vorticity and high strain;in contrast,negative values of potential vorticity are more likelyto appear in the surface layer with poor fluid stability.Furthermore,we discuss the main energy sources and control factors of SMPs by analyzing their energetics.

关 键 词：南海 次中尺度 季节变化 上层海洋 空间差异 

分 类 号：P731.27[天文地球—海洋科学]