北太平洋涡旋对基于细尺度参数化的海洋内部混合的影响

INFLUENCE OF EDDY ON OCEAN INTERNAL MIXING IN NORTH PACIFIC BY FINE-SCALE PARAMETERIZATION

基于Vector Geometry方法对2016-2018年的高度计资料进行涡旋识别,并使用细尺度参数化方法和Argo数据计算了涡旋附近的海洋内部扩散率,分析了北太平洋的涡旋对海洋内部混合的影响。结果显示,研究区域在涡旋影响下的平均扩散率比无涡旋影响下的值大6%,并且气旋涡增强了600-1200m深度的混合,对600-900m深度的混合影响最大,可达18%;反气旋涡明显增强了300-900m深度的混合,但对900-1200m深度的混合没有明显影响。随着与涡旋中心距离的增大,涡旋外围混合扩散率缓慢减小,涡旋内部混合扩散率变化不明显,此结果与2014年3-10月在24°-36°N、132°-152°E区域的一个个例分析结果一致。此外,随着涡旋强度的增大,海洋内部混合明显增强。统计结果表明,在研究区域,90%的扩散率值在10^-5.5-10^-4m^2/s范围内。

Using the vector geometry method,eddy in North Pacific was identified with altimeter data in 2016-2018,and the ocean internal diapycnal mixing diffusivity near the eddy was calculated by fine-scale parameterization and the Argo data.The influence of the eddy on the internal mixing was analyzed.Results show that the average diffusivity of the study region with the eddy influence was 6%greater than that without the eddy influence.The cyclonic eddy enhanced the mixing in 600-1200 m depth in maximum at 600-900 m depth where the average diffusivity reached 18%.The mixing at 300-900 m depth was enhanced greatly by anticyclonic eddy,but the effect at 900-1200 m was not obvious.With the distance increase from the eddy center,the diffusivity outside the eddy decreased gradually but inside the eddy did not change significantly.The result has been verified in a case study in the region of 24°-36°N/132°-152°E from March to October 2014.Moreover,with the increase in the eddy intensity,the diapycnal mixing was enhanced largely.Statistics show that 90%of the diffusivity was in the range of 10^–5.5-10^–4 m^2/s.