海洋环流与波动重点实验室知识库

本文基于布放在印尼哈马黑拉海的贾宜洛洛海峡内的潜标所观测到的长时间序列全水深流速剖面数据，开展了内潮流和垂向剪切的特征研究。首次解析了内潮流结构及其动力学特征，并研究了海峡内垂直剪切的结构和动力学成因。

潜标观测显示，贾宜洛洛海峡内具有复杂的潮流结构。从全深度海流剖面测量中提取得到的正压潮流显示，主要的M₂、K₁和O₁潮汐流振幅分别为13.5 cm s^-1、11.0 cm s^-1和7.6 cm s^-1，最大潮流方向分别为正北方向顺时针旋转34.5º、63.1º和75.2º，基本呈往复式流动。贾宜洛洛海峡的潮流动能约占总动能的50%，以低阶斜压模态为主，其中M₂潮流是最主要的潮流分量。观测到了D₃和D₄等高频内潮，一般认为来自于线性潮与地形之间包括共振在内的非线性作用，其斜压结构与M₂内潮相似，但受到高阶斜压模态的强控制。这是印尼贯穿流东通道入口处的贾宜洛洛海峡内复杂的内潮流垂直结构首次被观测揭示，对于未来的海洋环流与气候数值模拟、垂直湍流混合研究及其在全球海洋和气候中的作用等有重要指导意义。

印度尼西亚海域的湍流混合对全球海洋大输送带的输热储热和水团转换等起重要作用。湍流混合通常认为是由海流的垂直剪切不稳定引起的，观测显示贾宜洛洛海峡的湍流混合系数大于一般开阔大洋一到两个数量级，但是由于缺乏海流观测数据，造成湍流混合的动力学成因一直不清楚。传统上，印尼海的湍流混合主要关注内潮流的剪切不稳定与数值模拟。然而，通过对贾宜洛洛海峡的两年系泊流速剖面的分析，我们发现内潮流在全部的垂直剪切中只起到了次要作用。发现主导着整个水柱垂直剪切的是连续频谱的高频内波，其在500米以下占总剪切的近70%。这些高频内波可以由内潮和环流通过非线性效应激发，其能量串级作用受到了印度尼西亚海域复杂地形的影响。我们期望未来的研究将进一步探讨印度尼西亚海域的剪切混合动力学成因，该过程是理解海洋储热储碳以及全球气候变化的关键过程。

This study investigates long-term time series full-depth current profiles obtained from moored instruments deployed at the entrance of the Indonesian Throughflow (ITF) in the Halmahera Sea. We analyze the flow structure and its dynamic properties within the Jailolo Strait, and subsequently explore the vertical shear mixing structure and dynamics, as well as the presence of nonlinear effects.

The Jailolo Strait has a complex vertical tidal current structure. Barotropic tides were extracted from the full-depth current profile measurements, showing the dominant M₂, K₁, and O₁ tidal currents with amplitudes of 13.5 cm s^-1, 11.0 cm s^-1 and 7.6 cm s^-1, in nearly reciprocating rotation at 34.5º, 63.1º, and 75.2º clockwise from due North.  The internal tidal currents in the Jailolo Strait contributing to about 50% of the total kinetic energy are found to be dominated by the low baroclinic modes, with M₂ tide as the most dominant tidal constituent. High-frequency internal tides of D₃ and D₄ are observed, with baroclinic structure similar to that of M₂ tides, and are suggested to be stimulated by nonlinear processes. The complicated vertical structure of tidal currents in the Jailolo Strait is disclosed for the first time in history. Its potential impact on vertical turbulent mixing suggests its importance in global ocean circulation and climate.

The turbulent mixing in the Indonesian seas contributes to the heat sequestration and water mass transformation. By observation, the mixing coefficient in the Jailolo Strait is one to two orders of magnitude greater than that of the typical open ocean. The turbulent mixing was traditionally attributed primarily to the vertical share of tidal currents. Here we show, using two-year moored current meter profiles in the Halmahera Sea, that tidal currents play a secondary role in the sheared instability.  Instead, continuous-spectrum super-tidal Internal Gravity Waves (IGWs) are found to dominate the vertical shear throughout the water column , accounting for nearly 70% of the total shear below 500 m. The IGWs appear to be fueled by the internal tides and the subtidal ITF, the energy cascading of which is known due to the complicated topography within the Indonesian seas. We anticipate that our study will herald further investigations into the sheared mixing in the Indonesian seas, a process crucial for understanding heat and CO₂ sequestration and global climate changes.

第1章 绪论... 1

1.1 研究背景与意义... 1

1.2 研究现状... 3

1.2.1 印尼贯穿流的研究历史... 3

1.2.2 哈马黑拉海与贾宜洛洛海峡的观测研究... 5

1.2.3 印度尼西亚海的潮与混合... 7

1.3 本文研究内容... 8

第2章 数据和方法... 10

2.1 观测数据... 10

2.1.1 潜标观测的流速数据... 10

2.1.2 温盐观测数据... 11

2.1.3 海峡地形观测数据... 11

2.2 全球地形资料... 11

2.3 风场资料... 12

2.4 研究方法... 12

2.4.1 潜标流速处理和质量控制... 12

2.4.2 功率谱密度... 12

2.4.3 S_TIDE.. 13

2.4.4 垂向剪切... 13

2.4.5 混合系数的估算... 14

2.4.6 临界地形坡度... 15

第3章 贾宜洛洛海峡的潮流结构... 16

3.1 分潮流垂向结构... 16

3.2 潮流动能... 22

3.3 小结... 23

第4章 贾宜洛洛海峡的剪切与混合... 24

4.1 剪切结构... 24

4.2 混合系数的估算... 28

4.3 小结... 30

第5章 总结和展望... 31

5.1 主要结论... 31

5.2 未来工作展望... 31

参考文献... 34

致谢... 40

作者简历及攻读学位期间发表的学术论文与其他相关学术成果    42