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徐鹏昭,杨伟,赵亮,魏皓,聂红涛.渤海弱层化期湍流混合观测特征分析[J].海洋学报,2020,42(3):1-9
渤海弱层化期湍流混合观测特征分析
Observations of turbulent mixing in the Bohai Sea during weakly stratified period
投稿时间:2019-01-28  修订日期:2019-08-18
DOI:10.3969/j.issn.0253-4193.2020.03.001
中文关键词:  湍动能耗散率  垂向湍扩散系数  渤海
英文关键词:turbulent kinetic energy dissipation rate  vertical eddy diffusivity  Bohai Sea
基金项目:国家重点研发计划(2017YFC1404403,2016YFC1401401);国家自然科学基金(41876018,41906006);天津市自然基金(16JCQNJC08000)。
作者单位E-mail
徐鹏昭 天津大学 海洋科学与技术学院, 天津 300072  
杨伟 天津大学 海洋科学与技术学院, 天津 300072 yangwouc@163.com 
赵亮 天津科技大学 海洋与环境学院, 天津 300457  
魏皓 天津大学 海洋科学与技术学院, 天津 300072  
聂红涛 天津大学 海洋科学与技术学院, 天津 300072  
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中文摘要:
      利用2017年9月在渤海共享航次中取得的湍流混合直接观测数据,本文研究了渤海海域湍流混合的空间分布特征及有关的影响因素。9月观测海区水体垂向层结较弱,莱州湾受黄河冲淡水影响出现高温低盐结构,位于渤海中央浅滩南北两侧洼地的双中心冷水结构依旧存在。湍流观测结果表明湍动能耗散率在10-9~10-5 W/kg之间变化,统计上满足对数正态分布。耗散率强值区出现在辽东湾及渤海湾湾口近岸处,相应的垂向湍扩散系数约为10-6~10-2 m2/s。垂向上,水体表、底层混合较强,进一步研究发现弱层化水体的平均湍动能耗散率〈ε〉与风速和正压潮流速的大小存在正相关关系。另一方面,耗散率ε与浮性频率N近似满足ε=2.0×10-8 +3.0×10-7N2/N02-5的拟合函数关系,反映了层化对水体垂向混合的抑制作用。
英文摘要:
      Based on the direct turbulence observations in the Bohai Sea during September 2017, this study investigates the spatial distribution of turbulent mixing in the Bohai Sea and the associated influencing factors. The water column was weakly stratified during the observation period. As influenced by the freshwater input from Yellow River, relatively warm and fresh water was found in the Laizhou Bay. The typical south-north dual-core cold bottom water structure still exited in the central Bohai Sea during the observation period. The observed turbulent kinetic energy (TKE) dissipation rate ε ranged from 10-9 to 10-5 W/kg and statistically satisfied the lognormal distribution. Intensified mixing was found at the nearshore region of the Liaodong Bay and the Bohai Bay. The corresponding vertical eddy diffusivity was about 10-6~10-2 m2/s. In the vertical direct direction, strong mixing occurred near the sea surface and bottom layers. Further analysis shows that the station-averaged TKE dissipation rate are positively related to the wind speed and barotropic tidal velocity. On the other hand, the dissipation rate and buoyancy frequency N satisfied the power function relationship of ε=2.0×10-8 +3.0×10-7(N2/N02)-5 indicating that inhibition effect of stratification on turbulent mixing.
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