| LI Mingming,XIE Lingling,ZONG Xiaolong,ZHANG Shuwen,ZHOU Lei,LI Junyi. 2018. The cruise observation of turbulent mixing in the upwelling region east of Hainan Island in the summer of 2012. Acta Oceanologica Sinica, 37(9):1－12 |
| The cruise observation of turbulent mixing in the upwelling region east of Hainan Island in the summer of 2012 |
| 2012年夏季海南岛东岸上升流区的混合观测 |
| Received:December 25, 2017 |
| DOI：10.1007/s13131-018-1260-y |
| Key words:coastal upwelling mixing turbulent kinetic energy dissipation rate eddy diffusivity South China Sea |
| 中文关键词: 沿岸上升流 混合 湍动能耗散率 涡流扩散系数 南海 |
| 基金项目:The National Natural Science Foundation of China under contract Nos 41476009, 41776034 and 41476010; the Natural Science Foundation of Guangdong Province of China under contract No. 2016A030312004; the Global Air-Sea Interaction Project of State Oceanic Administration under contract No. GASI-IPOVAI-01-02; the Laboratory of Tropical Ocean Open Foundation under contract No. LT1404. |
| Author Name | Affiliation | E-mail | | LI Mingming | Guangdong Key Laboratory of Coastal Ocean Variability and Disaster Prediction, Guangdong Ocean University, Zhanjiang 524088, China | | | XIE Lingling | Guangdong Key Laboratory of Coastal Ocean Variability and Disaster Prediction, Guangdong Ocean University, Zhanjiang 524088, China | llingxie@163.com | | ZONG Xiaolong | Physical Oceanography Laboratory, Ocean University of China, Qingdao 266003, China | | | ZHANG Shuwen | Guangdong Key Laboratory of Coastal Ocean Variability and Disaster Prediction, Guangdong Ocean University, Zhanjiang 524088, China | | | ZHOU Lei | Institute of Oceanography, Shanghai Jiaotong University, Shanghai 200240, China
Laboratory for Regional Oceanography and Numerical Modeling, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266200, China | | | LI Junyi | Guangdong Key Laboratory of Coastal Ocean Variability and Disaster Prediction, Guangdong Ocean University, Zhanjiang 524088, China | |
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| Abstract: |
| The turbulent mixing in the upwelling region east of Hainan Island in the South China Sea is analyzed based on in situ microstructure observations made in July 2012. During the observation, strong upwelling appears in the coastal waters, which are 3℃ cooler than the offshore waters and have a salinity 1.0 greater than that of the offshore waters. The magnitude of the dissipation rate of turbulent kinetic energy ε in the upwelling region is O (10-9 W/kg), which is comparable to the general oceanic dissipation. The inferred eddy diffusivity Kρ is O (10-6 m2/s), which is one order of magnitude lower than that in the open ocean. The values are elevated to Kρ≈O (10-4 m2/s) near the boundaries. Weak mixing in the upwelling region is consistent with weak instability as a result of moderate shears versus strong stratifications by the joint influence of surface heating and upwelling of cold water. The validity of two fine-scale structure mixing parameterization models are tested by comparison with the observed dissipation rates. The results indicate that the model developed by MacKinnon and Gregg in 2003 provides relatively better estimates with magnitudes close to the observations. Mixing parameterization models need to be further improved in the coastal upwelling region. |
| 中文摘要: |
| 本文根据2012年7月在南海北部海南岛东岸上升流区进行的现场微结构流速剪切观测分析了该区域的湍流混合特征。观测期间，近岸水域已形成强上升流，其中心区域水体温度比周围水体低3℃，盐度高1psu。上升流区湍动能耗散率ε量级为10-9 W kg-1，与外海耗散率相当。由此计算出的扩散率Kρ比外海低一个量级，为10-6 m2 s-1。扩散率大值出现在边界附近，约10-4 m2 s-1。该区域较弱的混合强度与较低的不稳定性相一致，是中等强度的剪切与由表层加热和下层冷水上涌导致的强层结之间共同作用的结果。本文还利用细结构流速观测数据对两种参数化模型在沿岸上升流区的适应性进行了检验。结果表明MacKinnon和Gregg于2003年提出的参数化模型估算结果与观测值大小最接近，但将参数化模型应用于沿岸上升流区前仍需对模型进一步改进。 |
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