黑潮延伸体海域典型涡旋的次中尺度特征分析*

本文基于卫星遥感资料和高分辨率ROMS(Regional Ocean Modeling System)数值模拟结果, 对黑潮延伸体海域典型中尺度涡旋的次中尺度特征进行了探讨。卫星观测和模拟结果显示, 黑潮延伸体涡旋海域伴随着活跃的次中尺度现象。涡旋演变与多尺度能量分析结果表明, 涡旋海域次中尺度动能的强弱与涡旋海域地转流动能有着密切联系, 锋生可能是涡旋边缘次中尺度动能增强的重要机制。次中尺度现象在中尺度涡旋海域具有沿地转流方向的复杂涡丝状结构特征, 意味着涡旋边缘较强的水平浮力梯度和地转流侧向剪切为次中尺度过程形成与发展提供了有利条件。此外, 垂向结构分析表明, 次中尺度过程能引起较大的垂向速度, 最大可达100m·day^-1, 该垂向速度可以影响至混合层下200m深度处, 对海洋内部的垂向物质能量交换、海—气相互作用等有着重要的影响。

Submesoscale characteristics of a typical anticyclonic mesoscale eddy in Kuroshio Extension*

Using satellite measurements and high-resolution ROMS simulations, we analyze submesoscale characteristics of a typical anticyclonic mesoscale eddy in the Kuroshio Extension. Both satellite observations and high-resolution simulations show obvious submesoscale phenomena in the vortex region in the Kuroshio Extension. Our analysis results show that the strength of submesoscale kinetic energy is in close connection with kinetic energy of geostrophic velocity, which means that the frontogenesis may be an important way to enhance the submesoscale kinetic energy in the eddy periphery. Our analysis of the eddy’s vertical constructure shows submesoscale process can induce strong vertical velocity, which can be up to 100 m·day^-1. The strong vertical velocity can reach a depth of hundreds of meters, indicating that submesoscale process can provide an efficient way for sea surface-internal material exchanging and air-sea interactions.