地中海涡旋的垂向结构与物理性质

摘要

Based on the new data inverted from a new seismic oceanography method, this paper will analyze the vertical structure and physical properties of a Mediterranean eddy (Meddy) , e. g. temperature, density, sound velocity and impedance, especially some fine structure and mixing mechanism. Our research shows that; (1) One Meddy usually includes Meddy Core Water and Meddy Mixed Water, this two-component structure can be revealed from the temperature, sound velocity and impedance section. (2) Meddy Core Water isn t smoothly stratified or stable as thought, however there is weak mixing process within it. (3) In the upper and lateral region of a Meddy, the mixing process is very complex. In addition to salt fingers, internal wave is also a very significant mixing process in the lower region. (4) The density structure of Meddy Core Water is smoothly stratified and stable; however, due to the complex mixing mechanism, the density structure of Meddy is disturbed and density inversion shows even in some region. (5) The Meddy doesn t show a strictly symmetrical structure and the lower boundary between Meddy Core Water and background seawater is more obvious than the upper one. The physical properties provided by the new seismic oceanography inversion method can be used for more accurate, more precise and higher resolution research and help further studies of Meddy kinematics and dynamics.%本文利用地震海洋学新的反演结果,对地中海涡旋的温度、密度、声速以及波阻抗等物理性质进行了详细的分析与讨论,特别对地中海涡旋的一些细结构、混合过程进行了相关描述.研究分析取得以下认识:(1)涡旋具有涡旋核心水与涡旋混合水双层结构,这种结构特征可以在温度图、声速图和波阻抗图中识别出来；(2)涡旋核心水并不是均匀的稳定结构,内部有微弱的混合作用；(3)在涡旋上部以及周围边缘区域,海水的混合比较复杂；在涡旋下部边缘区域,除了有小尺度的盐指混合,内波也是非常重要的动力混合作用；(4)海水密度在涡旋核心水的分布比较稳定,成层性较强,在混合水区域由于不同的混合作用及其强烈程度不同,会发生波动甚至反转；(5)涡旋本身并不是一个严格对称的结构,涡旋与背景海水的上部以及周围边界比较模糊和复杂,而涡旋下部边界则比较明显.地震海洋学反演提供的涡旋物理性质数据能够为涡旋进一步的研究提供更为准确、更高精度以及更高分辨率的参考数据,同时对涡旋的运动学以及动力学研究提供了更进一步的研究方法和研究方向.