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| 雅浦-马里亚纳海沟连接区深层流季节内变异的特征和机制 |
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赵秋雅1,2, 汪嘉宁2,3,4, 张航2,4, 张志祥2, 马强2, 马卫东2,4, 王凡2,3,4, 杨红卫1
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1.山东科技大学数学与系统科学学院 山东青岛 266590;2.中国科学院海洋环流与波动重点实验室 山东青岛 266071;3.崂山实验室海洋动力过程与气候功能实验室 山东青岛 266237;4.中国科学院大学海洋学院 山东青岛 266400
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| 摘要: |
| 雅浦-马里亚纳海沟连接区东深水通道是太平洋深层经向翻转环流携带南极绕极水进入西太平洋的首要入口。基于高分辨率的再分析数值模型结果, 研究发现该通道深层流速和温度具有显著的40~90 d周期的季节内变异, 且季节内变异强度随深度的增加而增加, 进一步研究揭示地形罗斯贝波(topographic Rossby waves, TRW)是引起上述季节内变异的主要原因, TRW波解可以解释深层流和温度季节内振幅的垂向变化。通过建立全水体的动力关联研究发现TRW在不同时刻具有不同的能量来源, 首先次表层强涡旋经过时可以通过位涡守恒激发深层的TRW; 第二, 大洋中层存在的强涡旋也可激发深层的TRW; 第三, 深层平均流可以主要通过正压不稳定过程向季节内TRW提供能量。 |
| 关键词: 雅浦-马里亚纳海沟连接区 季节内变异 地形罗斯贝波 次表层和中层中尺度涡 正斜压不稳定 |
| DOI：10.11693/hyhz20221200330 |
| 分类号:P721 |
| 基金项目:国家自然科学基金,91958204号,42222602号;崂山实验室科技创新项目,LSKJ202203100号。 |
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| CHARACTERISTICS AND MECHANISM FOR INTRASEASONAL VARIABILITY OF DEEP OCEAN CURRENTS AT THE YAP-MARIANA JUNCTION |
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ZHAO Qiu-Ya1,2, WANG Jia-Ning2,3,4, ZHANG Hang2,4, ZHANG Zhi-Xiang2, MA Qiang2, MA Wei-Dong2,4, WANG Fan2,3,4, YANG Hong-Wei1
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1.School of Mathematics and Systems Science, Shandong University of Science and Technology, Qingdao 266590, China;2.Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China;3.Laboratory for Ocean Dynamics and Climate, Laoshan Laboratory, Qingdao 266237, China;4.College of Marine Science, University of Chinese Academy of Sciences, Qingdao 266400, China
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| Abstract: |
| The eastern deep channel at the Yap-Mariana Junction is the choke site for the deep limb of Pacific meridional overturning circulation carrying the Circumpolar Deep Water into the western Pacific Ocean. Based on outputs from a high-resolution reanalysis numerical product, we find that the deep zonal velocity and temperature have significant intraseasonal variability with periods of 40~90 days. Such intraseasonal variability intensifies with depth. We reveal that the deep intraseasonal variability arises from topographic Rossby waves (TRW). TRW’s theoretical wave solution can explain most of the vertical distributions of deep intraseasonal velocity and temperature amplitudes. Through the establishment of a dynamic connection over the full-depth water column, we suggest that TRW has different energy sources during different periods. First, the strong subsurface eddy can trigger the TRW through the conservation of potential vorticity. Secondly, the strong interior eddy at the intermediate depth can also stimulate TRW through the conservation of potential vorticity. Thirdly, the barotropic instability of the deep ocean mean currents can provide energy for the TRW. |
| Key words: Yap-Mariana Junction intraseasonal variability topographic Rossby waves the subsurface and intermediate mesoscale eddies barotropic-baroclinic instability |