Spatial and temporal variability of turbulent mixing in the near-field of the Changjiang River

IOCAS-IR

	Spatial and temporal variability of turbulent mixing in the near-field of the Changjiang River
	WANG Jianfeng ; YU Fei ; REN Qiang; WEI Chuanjie
发表期刊	Journal of Oceanology and Limnology
ISSN	2096-5508
	2020-07-15
出版年	2020
卷号	v.38 期号:04 页码:243-257
文献类型	CNKI期刊论文
摘要	Based on field hydrological,micro structural,and shipboard Acoustic Doppler Current Profiler data,we quantified the spatial and temporal variability of turbulent mixing in the near-field Changjiang(Yangtze) River plume.The surface dissipation rate(s) changed by three orders of magnitude from near-field(10~(-4) W/kg) to far-field(10~(-7) W/kg) plumes,indicating a decrease with distance from the river mouth.Below the river plume,ε changed with depth to 10~(-8) W/kg,and increased to 10~(-6) W/kg at the layer where the Taiwan Warm Current(TWC) intruded.Thus,ε in the near-field plume showed three layers:surface layer in the river plume,middle layer,and lower TWC layer.In the river plume,the strongest ε and turbulent diffusivity(Kz)were greater than 10~(-4) W/kg and 10~(-2) m~2/s,respectively,during strong ebb tides.A three-orders-of-magnitude change in ε and Kz was observed in the tidal cycle.The depth of the halocline changed with,tidal cycles,and stratification(N~2) varied by one order of magnitude.Stratification in the TWC layer followed the distribution of the halocline,which is opposite to the dissipation structure.Tidal currents led to intrusion and turbulent mixing in the TWC layer.During ebb tides,ε and Kz were as strong as those measured in the river plume,but did not last as long.The structure of the velocity shear was similar to the dissipation rate in both the river plume and TWC layer,whereas the velocity shear in the TWC layer did not match the stratification structure.In the high dissipation rate area,the gradient Richardson number was smaller than the critical value(Ri_g<1/4).The Rig structure was consistent with shear and dissipation distributions,indicating that turbulent mixing in the near-field plume was controlled by a combination of shear induced by the discharged river flow and tidal current.
关键词	Changjiang River near-field plume turbulent mixing observation microstructure
CNKI专辑号	A;C;
CNKI专辑名称	基础科学;工程科技Ⅱ辑;
CNKI专题号	A012;C037;
CNKI专题名称	地球物理学;水利水电工程;
分类号	TV133
收录类别	中科院核心 ; 中科院扩展
语种	英文;
资助项目(基金）	Supported by the National Natural Science Foundation of China(NSFC)(No.41706012) ; the National Key Research and Development Program of China (No.2017YFC1403401) ; the National Natural Science Foundation of China (NSFC) Innovative Group Grant (No.41421005) ; the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1406401) ; the Strategic Priority Research Program of Chinese Academy of Sciences (No.XDA11020301)
文献类型	CNKI期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/188147
专题	中国科学院海洋研究所
作者单位	1.CASKeyLaboratoryofOceanCirculationandWaves,InstituteofOceanology,ChineseAcademyofSciences 2.CenterforOceanMega-Science,ChineseAcademyofSciences 3.PilotNationalLaboratoryforMarineScienceandTechnology(Qingdao) 4.UniversityofChineseAcademyofSciences
推荐引用方式 GB/T 7714	WANG Jianfeng,YU Fei,REN Qiang,et al. Spatial and temporal variability of turbulent mixing in the near-field of the Changjiang River. 2020.