加拿大海盆冰下表层海水湍扩散系数估计

The Estimation of Vertical Turbulent Diffusivity in the Surface Layer in the Canada Basin

海洋的湍粘性系数和湍扩散系数是研究海洋动量传输、热扩散和物质扩散的物理基础,是海洋模式的重要参数。北冰洋是海冰覆盖的海洋,其湍粘性系数和湍扩散系数与其他大洋有显著不同。本文以Pacanowski&Philander的参数化方案为基础,采用二次北极科考的连续观测冰站和单次观测冰站的资料,定量计算了加拿大海盆74°N^78°N,144°W^164°W区域冰下60 m以浅的垂向湍粘性系数v和湍扩散系数kT,并分3个区域比较。结果表明:v和kT的垂向分布具有较好的一致性,表层和60 m处量值较大,中间较小;区域的不同主要体现在24 m以浅。

The vertical eddy diffusivity v and eddy viscosity kT are important for the description of the vertical transfer of substance in dynamical studies and various numerical models. In the Arctic Ocean, which is an icecovered ocean, the turbulent parameters are significantly different from the other oceans, and the characteristics are still not clear due to a lack of observations. Using the temperature, salinity and current profile data in the Canada Basin（74°N- 78°N, 144°W- 164°W） obtained from the Chinese Arctic Research Expedition cruise of summer 2003, we calculate the vertical distributions of v and kT. Also, we compare and analyze the values of v and kT of different sea areas. The method we used here was proposed by Pacanowski and Philander, which determined the vertical eddy diffusivity and eddy viscosity by the Richardson Number. The results show that the distributions of v and kT are consistent in some respects： large in both surface and at the depth of 60 m; smaller in the middle layer. While the differences of the sea areas mainly manifest themselves at depths less than 24 m