垂直湍流输送对大洋的重力位能和混合过程的影响  

Impact of Vertical Turbulence on Ocean Gravitational Potential Energy and the Tracer Mixing Process

作　　者：张宇[1] 林一骅 王辉[1] 

机构地区：[1]国家海洋环境预报中心,北京100081 [2]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029

出　　处：《大气科学》2014年第5期838-844,共7页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金资助项目41175058

摘　　要：利用WOA09(World Ocean Atlas 2009)全球大洋温盐客观分析数据,计算了不同湍流垂直混合系数下全球大洋重力位能的变化,并分析了混合系数、浮力频率和重力位能变化之间的关系。在此基础上,进一步探讨了湍流混合造成的能量转换对湍流参数化的影响。结果表明,大洋中的垂直湍流运动不仅仅是动能能汇,而且是一个重要的外部能量转化为重力位能的途径。垂直湍流增加的重力位能在混合系数取0.1 cm2 s-1时为0.08 TW,参考前人研究结果,外部能量输入甚至可引起等效于全球平均12 cm2 s-1的垂直混合系数。一般而言,层结越稳定、混合系数越大,垂直湍流对重力位能的影响也越大。考虑湍流动能可转化为重力位能后,参数化方案可以得到和实际观测更接近的湍流动能耗散率和混合系数。Using a WOA09 （World Ocean Atlas 2009） data set of objectively analyzed in situ temperature and salinity, we calculate ocean gravitational potential energy （GPE） and investigate the relationships between the mixing coefficient, buoyancy frequency, and GPE. On that basis, we further explore the impact of energy conversion, caused by turbulent mixing, on turbulent parameterization. The research shows that ocean vertical turbulence is not only a kinetic energy sink but also an important way of external energy transformation to GPE. When the mixing coefficient is 0.1 cm2s-1, GPE will increase 0.08 TW. Based on the results of other authors, we conclude that external energy can induce a global average mixing coefficient of up to 12 cm2s-1. In general, the more stable the stratification of the ocean and the larger the mixing coefficient, the higher the GPE increase. Parameterization can obtain more realistic results with careful treatment of turbulent kinetic energy conversion to GPE.

关 键 词：混合系数 重力位能 湍流动能 耗散率 湍流混合参数化 

分 类 号：P731[天文地球—海洋科学]