| 引用本文: | 侯剑浩,张林林,徐勤博,王震,严啸峦,康霖.岛屿对西太平洋纬向急流强度的调控作用[J].海洋科学,2025,49(7):1-18. |
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| 岛屿对西太平洋纬向急流强度的调控作用 |
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侯剑浩1,2, 张林林2, 徐勤博2, 王震1, 严啸峦2, 康霖3
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1.山东科技大学, 山东 青岛 266590;2.中国科学院海洋研究所 海洋环流与波动实验室, 山东 青岛 266071;3.海南热带海洋学院 崖州湾创新研究院, 海南 三亚 572022
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| 摘要: |
| 西太平洋环流在全球物质能量输运与气候系统中扮演着关键角色。以往研究表明, 传统认知的风生环流之下存在南北交替的纬向急流。然而, 在关于纬向急流的研究中, 观测与数值模拟间存在显著差异: 观测显示北太平洋纬向急流的分布呈“西强东弱”的特征, 而模式模拟结果却呈现“东强西弱”的相反格局, 且这一差异的成因尚未明确。基于此, 本研究的核心目的为: 验证岛屿效应是导致上述差异的关键因素, 聚焦岛屿的物理作用, 明确岛屿属性对西太平洋纬向急流的调控作用, 进而为解决观测与模拟的矛盾提供依据。为去除复杂因素的影响, 本研究采用1.5层约化重力模式, 在纬向风应力驱动下, 通过控制变量的方法设计一系列敏感性实验, 系统性地引入了不同位置(经、纬度)、不同大小以及有无侧摩擦, 以评估岛屿几何形态与物理参数对纬向急流的影响。实验结果揭示了岛屿对纬向急流的显著调控作用。首先, 岛屿的引入能在其西侧激发出强烈的纬向急流, 北侧为东向急流, 南侧为西向急流。其次, 这种调控效应具有强烈的位置依赖性: 当岛屿纬度变化时, 对急流的增强效应在20°N附近达到峰值; 当岛屿经度变化时, 峰值则出现在110°E附近。岛屿尺度同样影响急流结构: 随着岛屿面积增大, 其西侧增强的急流所覆盖的纬度范围随之拓宽, 但急流的核心强度反而减弱。最后, 模式实验表明, 岛屿侧摩擦对急流的产生起抑制作用。岛屿是调控西北太平洋纬向急流强度与空间结构的关键因子, 其位置、尺度及侧摩擦等属性会通过不同机制影响急流特征。 |
| 关键词: 西太平洋 纬向急流 约化重力模式 |
| DOI：10.11759/hykx20240524002 |
| 分类号:P731.21 |
| 基金项目:国家自然科学基金项目(42576027);中国科学院战略性先导科技专项(XDB42010105);国家自然科学基金项目(42506002,42122041,42449909);泰山学者项目(tsqn202103128) |
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| Role of islands in regulating zonal jets strength in the western Pacific Ocean |
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HOU Jianhao1,2, ZHANG Linlin2, XU Qinbo2, WANG Zhen1, YAN Xiaoluan2, KANG Lin3
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1.Shandong University of Science and Technology, Qingdao 266590, China;2.Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;3.Yazhou Bay Innovation Institute of Hainan Tropical Ocean University, Sanya 572022, China
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| Abstract: |
| The western Pacific circulation plays a pivotal role in global material and energy transport within the climate system. Previous studies have indicated that, beneath the conventionally recognized wind-driven circulation, zonal jets alternate between the Northern and Southern Hemispheres. However, substantial discrepancies exist between observations and numerical simulations, observations show a “stronger in the west, weaker in the east” distribution pattern for the North Pacific zonal jets, whereas numerical simulations show the opposite—“stronger in the east, weaker in the west.” The reason for this discrepancy remains unclear. Based on this, the core objectives of this study are as follows: to validate the island effect as the key factor driving the aforementioned discrepancy, to examine the physical role of islands, to clarify the regulatory influence of island attributes on the West Pacific zonal jets, and to provide a basis for resolving the contradiction between observations and simulations. To eliminate complex confounding factors, this study employed a 1.5-layer simplified gravity model. Under the driving force of zonal wind stress, a series of sensitivity experiments was designed using the controlled variable method. These experiments systematically introduced variations in island location (longitude and latitude), size, and the presence or absence of lateral friction to assess the influence of island geometry and physical parameters on the zonal jets. Experimental results reveal that islands exert a significant regulatory effect on the zonal jets. First, introducing islands generates intense zonal jets west of the island, with easterly jets to the north and westerly jets to the south. Second, this regulatory effect shows strong positional dependence: the jets-enhancing effect peaks near 20 °N as the island’s latitude varies, while the peak occurs near 110°E when the island’s longitude changes. Island scale also influences the jets structure: as the island surface area increases, the latitudinal extent of the enhanced jets west of the island broadens, while the core intensity of the jets weakens. Finally, model experiments indicate that lateral friction associated with islands suppresses jets formation. Through idealized numerical experiments, this study clearly identifies islands as a key factor regulating the intensity and spatial structure of the North Pacific zonal jets stream in the northwest Pacific. The location, scale, lateral friction, and other properties of islands influence jets characteristics through distinct mechanisms. This finding not only provides a novel physical explanation for the discrepancies between observations and simulations but also underscores the importance of accurately capturing island effects in ocean and climate models to enhance the simulation capability of the western Pacific circulation. |
| Key words: Western Pacific Ocean zonal jets reduced-gravity model |
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