南极普里兹湾海域湍流扩散系数估计

摘要

基于Thorpe尺度方法,利用CTD数据,计算了南极普里兹湾海域的Thorpe尺度和湍流扩散系数,分析了观测区域(64°～69°S,66°～80°E)湍流翻转现象的强弱及分布.结果表明,在海底和地形粗糙区存在较大的Thorpe尺度(较强湍流翻转)和湍流扩散系数,湍流扩散系数最大值能达到10-2m2/s量级,比平坦开阔海洋高2～3个数量级,部分观测站位的湍流扩散系数和湍动能耗散率表现出大-小-大的垂向分布结构,总水深较深的区域尤为明显;深水区域的浮力频率在海表面到500 m层比较大,浅水区域该现象不明显;湍动能耗散率在(67.25°S,73°E)周围和经度为78°E的各站位都表现相对较大,能达到10-6 w/kg量级,个别站位甚至能达到10-5 w/kg量级.%Thorpe scale and turbulent diffusivities in Prydz Bay of Antarctica were calculated based on Thorpe method and Conductivity-Temperature-Depth data.The strength of turbulent overturn was analyzed and its spatial distribution was also investigated.The results show that the larger Thorpe scale and turbulent diffusivities occur in rough topographic area and near the sea floor,and the maximum value of turbulent diffusivities exceeds 10-2 m2/s,which is about two or three orders of magnitude larger than that in the open ocean.Turbulent diffusivities and dissipation rate of turbulent kinetic energy show high-low-high verticalstructure in some observational stations,especially in deep area.The larger values of buoyancy frequency appear in upper 500 m water column in deep area,but this phenomenon is not obvious in shallow area.The dissipation rates of turbulent kinetic energy in the stations around the point(67.25°S,73°E) and along the 78° E sections are quite large,which exceed 10-6 w/kg,and even reach 10-5 w/kg in a few stations.