海洋学报（中文版）
海洋學報（中文版）
해양학보（중문판）
ACTA OCEANOLOGICA SINICA
2014年
1期
7-19
,共13页
李燕%乔方利%戴德君%马洪余
李燕%喬方利%戴德君%馬洪餘
리연%교방리%대덕군%마홍여
Ekman流%稳定性分析%次级环流(二次流)
Ekman流%穩定性分析%次級環流(二次流)
Ekman류%은정성분석%차급배류(이차류)
upper mixed layer%Ekman flow%secondary circulation%stability analysis
海洋上混合层中的次级环流可通过物质和能量的垂直输运和混合过程把海洋表层的热量、动量与物质携带到次表层，对海洋上层次级环流生成机制的研究可以丰富对上层海洋的理解和认识。文中利用线性稳定性理论讨论了经典海表Ekman流的不稳定性，提出Ekman流的不稳定性可生成一种新型的次级环流。这种次级环流的空间尺度与雷诺数、Ekman流的垂向衰减速率、水平湍黏性系数与垂向湍黏性系数比值等密切相关，尺度范围从数十米到数千米。数十米量级的次级环流其垂向结构以及次级环流流轴与主流场偏角都与Langmuir环流的特征极为相似，是Langmuir 环流形成机制的一种新解释。千米量级的次级环流能够解释黄海浒苔的条带分布。此外，所得次级环流的流轴与主流之间的偏角与科氏力有显著关系，北半球次级环流流轴偏向主流左侧，南半球反之。
海洋上混閤層中的次級環流可通過物質和能量的垂直輸運和混閤過程把海洋錶層的熱量、動量與物質攜帶到次錶層，對海洋上層次級環流生成機製的研究可以豐富對上層海洋的理解和認識。文中利用線性穩定性理論討論瞭經典海錶Ekman流的不穩定性，提齣Ekman流的不穩定性可生成一種新型的次級環流。這種次級環流的空間呎度與雷諾數、Ekman流的垂嚮衰減速率、水平湍黏性繫數與垂嚮湍黏性繫數比值等密切相關，呎度範圍從數十米到數韆米。數十米量級的次級環流其垂嚮結構以及次級環流流軸與主流場偏角都與Langmuir環流的特徵極為相似，是Langmuir 環流形成機製的一種新解釋。韆米量級的次級環流能夠解釋黃海滸苔的條帶分佈。此外，所得次級環流的流軸與主流之間的偏角與科氏力有顯著關繫，北半毬次級環流流軸偏嚮主流左側，南半毬反之。
해양상혼합층중적차급배류가통과물질화능량적수직수운화혼합과정파해양표층적열량、동량여물질휴대도차표층，대해양상층차급배류생성궤제적연구가이봉부대상층해양적리해화인식。문중이용선성은정성이론토론료경전해표Ekman류적불은정성，제출Ekman류적불은정성가생성일충신형적차급배류。저충차급배류적공간척도여뢰낙수、Ekman류적수향쇠감속솔、수평단점성계수여수향단점성계수비치등밀절상관，척도범위종수십미도수천미。수십미량급적차급배류기수향결구이급차급배류류축여주류장편각도여Langmuir배류적특정겁위상사，시Langmuir 배류형성궤제적일충신해석。천미량급적차급배류능구해석황해호태적조대분포。차외，소득차급배류적류축여주류지간적편각여과씨력유현저관계，북반구차급배류류축편향주류좌측，남반구반지。
The secondary circulation in the mixed layer of the upper ocean can bring the heat,momentum and mate-rial from the upper ocean to the subsurface which affects the vertical transport,exchange and mixing in this layer. The studies on the secondary circulation,including its formation mechanism and the interaction with other dynamic process,can enrich our understanding of the ocean upper layer.In this study,we use the linear stability theory to analyze stability of classical Ekman flow on the upper ocean,and present the idea that the instability of the Ekman flow can induced a new kind of secondary circulation.The space scales of this secondary circulation are closely re-lated with the Reynolds number,decaying rate of Ekman flow and the ratio between the horizontal and the vertical turbulent viscosity coefficients etc,and have a wide range from tens of meters to several kilometers.For the sec-ondary circulation of tens of meters,its vertical structure and the deflection angle between the axis of secondary circulation and the main flow are very similar to that of the Langmuir circulation,so this is a new explanation of the formation mechanism for Langmuir circulation.For the secondary circulation of kilometers,it may be responsi-ble for the band structure of surface drifting macroalgae in the western Yellow Sea.In addition,the deflection an-gle between the axis of the secondary circulation and the main flow is affected by the coriolis force,in the northern hemisphere the secondary circulation turns to the left of the main slow,and to the right in the southern hemi-sphere.
