摘要
基于全球海洋再分析模拟GLORYS2(Global Ocean Reanalysis Simulation 2)结果,分析了PN断面(126.0°E-128.2°E,1 000 m以浅)黑潮流速垂直结构的季节和年际变化,探讨了黑潮流速垂直结构形成的动力学机制。结果表明:1)PN断面黑潮夏季流量最大,春季次之,秋、冬季节最小;气候态平均的冬、夏季流速最大值都位于次表层,春、秋季节流速最大值位于表层;夏季相对流速较大、最大值深度较浅;等密线在黑潮主轴区下凹,冬季更为明显。流速最大值深度和密度水平梯度为零的深度均表现出了较大的年际差异,该年际变化甚至超过季节差异;2)流速与密度符合热成风关系。黑潮通量由太平洋大尺度风场及中尺度运动两者共同决定,但局地的热通量和环流对温盐的输运共同影响密度场,调节黑潮流速的垂直分布,影响水通量的分配及营养盐输运;3)有些年份夏季流速最大值出现在表层,可能是夏季西南季风诱导陆架水离岸输运进入黑潮上层导致的结果。非线性、非地转物理过程的影响没有考虑在本研究中,热成风关系能够解释黑潮流速垂直分布形成的部分原因。
The seasonal and inter-annual variations of vertical distribution of Kuroshio velocity and its formation mechanism are studied by analyzing the GLORYS2（Global Ocean Reanalysis Simulation 2） dataset at the PN section（126.0 °E-128.2 °E, depth less than 1000 m）. The results indicate that： 1） The maximum transport at PN section is in summer, followed by spring, and the minimum is in autumn and winter; the maximum velocities are located in the subsurface in both winter and summer with relatively larger velocity and shallower depth in summer; the velocity core is located in the surface in spring and autumn. The isopycnic line has a clear depression around the Kuroshio axis in winter.The depths of maximum velocity and zero horizontal density gradient both have significant seasonal and inter-annual variations, and the latter is even larger. 2） The distributions of velocity and density are in accordance with the thermal wind relation. Although the Kuroshio transport is determined by the large-scale wind field and meso-scale motion in the Pacific Ocean, local heat flux and thermohaline circulation will influence the density field and modify the vertical structure of Kuroshio velocity, which is actually the adjustment of allocation of water fluxes and nutrients transport. 3）Shelf water offshore transport into the Kuroshio upper layer induced by southwest monsoon may contribute to the maximum velocity up to the surface in summer. Nonlinear and nongeostrophic processes are not considered in this study,and the thermal wind relation accounts for part of the vertical structure of Kuroshio velocity.
出处
《海洋通报》
CAS
CSCD
北大核心
2014年第5期519-526,共8页
Marine Science Bulletin
基金
国家重点基础研究发展计划(973计划)(2011CB403606)
国家自然科学基金(41128006)
关键词
黑潮
流速垂直分布
热成风关系
PN断面
Kuroshio
vertical distribution of velocity
thermal wind relation
PN section
