一个考虑潮汐、中尺度涡和地形影响的南海底部环流诊断模型  

A diagnostic model of the South China Sea bottom circulation in consideration of tidal mixing,eddy-induced mixing and topography

作　　者：肖劲根[1,2] 谢强[1,3] 刘长建[1,4] 陈举[1] 王东晓[1] 陈美榕[5] 

机构地区：[1]中国科学院南海海洋研究所,热带海洋环境国家重点实验室,广东广州510301 [2]中国科学院研究生院,北京100049 [3]中国科学院三亚深海科学与工程研究所,海南三亚572000 [4]国家海洋局南海工程勘察中心,广东广州510300 [5]国家海洋局东海预报中心,上海200081

出　　处：《海洋学报》2013年第5期1-13,共13页

基　　金：国家自然科学基金(91228202);国家自然科学基金(41276024);中国科学院三亚深海科学与工程研究所知识创新工程领域前沿项目(SIDSSE-201205);三亚市院地科技合作项目(2012YD01)

摘　　要：本文构造了一个考虑潮汐、中尺度涡和地形影响下的南海底部环流诊断模型。在该模型中,潮汐混合和涡致混合引起的垂直速率用一个类似的改进参数化方案来表示。该模型结果显示在南海深层吕宋海峡"深水瀑布"和斜压影响最大,潮汐作用和中尺度涡影响次之,风场的影响最小。斜压影响的整体效应与其他因素相反。潮汐混合与涡致混合具有明显的地形依赖性。潮汐混合主要集中在南海北部海盆地形较为陡峭的陆坡区和南海中部海山区,而涡致混合主要集中在海盆西边界区以及中部海山区。在不考虑吕宋海峡"深水瀑布"、潮汐和中尺度涡的情况下(对应吕宋海峡关闭),南海底部环流为反气旋式环流。考虑吕宋海峡"深水瀑布"后,南海底层环流为气旋式环流,而潮汐混合和涡致混合起到加强整个气旋式环流强度的作用。此外,该模型还给出了南海底部环流量级大小与地形坡度之间的密切关系,即地形坡度较大的地方,其流速也大。这对于现场观测有着一定的参考意义。最后,本文用尺度分析的方法从理论上分析了该模型的适用性,证实了该模型具有一定的可靠性。This paper constructs a diagnostic model of the South China Sea bottom circulation in consideration of topography, tidal mixing and eddy-induced mixing. In this model, the tidal mixing and eddy-induced mixing are represented with modified similar mixing parameterizations. The results of the model show that Luzon overflow and baroclinic effect are largest,and tidal mixing and eddy-induced mixing are relative larger with Ekman pumping be- ing weakest. The effect of baroclinic forcing is opposite to other factors. The tide mixing is depended on the topog- raphy roughness, and mainly concentrated in the northern South China Sea slope where the topography is steep and around seamounts in central South China Sea basin while eddy-induced mixing is concentrated in western boundary and around seamouts. With Luzon overflow closing, the South China Sea bottom circulation is anticyclonic. With Luzon overflow unclosing, the South China Sea bottom circulation is cyclonic. Tidal mixing and eddy-induced mix- ing strengthen the magnitude of the cyclonic circulation. In addition, the model also gives the close relationship between the sea bottom circulation scale size and the slope of the topography. This means that the magnitude of velocity is larger with steeper topography. This gives some references for field observation. Finally, the paper analyzes the applicability of the model, and it is proved that this simple model has a certain reliability.

关 键 词：地形 潮汐混合 涡致混合 吕宋海峡“深水瀑布” 诊断模型 南海底层环流 

分 类 号：P722.7[天文地球—海洋科学] P731.21