On the Formation of a Subsurface Weakly Sheared Laminar Layer and an Upper Thermocline Strongly Sheared Turbulent Layer in the Eastern Equatorial Pacific: Interplays of Multiple-Time-Scale Equatorial Waves

doi:10.1175/JPO-D-19-0245.1

IOCAS-IR

	On the Formation of a Subsurface Weakly Sheared Laminar Layer and an Upper Thermocline Strongly Sheared Turbulent Layer in the Eastern Equatorial Pacific: Interplays of Multiple-Time-Scale Equatorial Waves
	Liu, Chuanyu 1,2,3,4; Wang, Xiaowei 1,2,3,4; Liu, Zhiyu 5,6; Koehl, Armin 7; Smyth, William D.8; Wang, Fan 1,2,3,4
	2020-10-01
发表期刊	JOURNAL OF PHYSICAL OCEANOGRAPHY
ISSN	0022-3670
卷号	50 期号:10 页码:2907-2930
通讯作者	Liu, Chuanyu(chuanyu.liu@qdio.ac.cn)
摘要	The origins of an observed weakly sheared nonturbulent (laminar) layer (WSL), and a strongly sheared turbulent layer above the Equatorial Undercurrent core (UCL) in the eastern equatorial Pacific are studied, based mainly on the data from the Tropical Atmosphere and Ocean mooring array. Multiple-time-scale (from 3 to 25 days) equatorial waves were manifested primarily as zonal velocity oscillations with the maximum amplitudes (from 10 to 30 cm s(-1)) occurring at different depths (from the surface to 85-m depths) above the seasonal thermocline. The subsurface-intensified waves led to vertically out-of-phase shear variations in the upper thermocline via destructive interference with the seasonal zonal flow, opposing the tendency for shear instability. These waves were also associated with depth-dependent, multiple-vertical-scale stratification variations, with phase lags of pi/2 or pi, further altering stability of the zonal current system to vertical shear. The WSL and UCL were consequently formed by coupling of multiple equatorial waves with differing phases, particularly of the previously identified equatorial mode and subsurface mode tropical instability waves (with central period of 17 and 20 days, respectively, in this study), and subsurface-intensified waves with central periods of 6, 5, and 12 days and velocity maxima at 45-, 87-, and 40-m depths, respectively. In addition, a wavelike feature with periods of 50-90 days enhanced the shear throughout the entire UCL. WSLs and UCLs seem to emerge without a preference for particular tropical instability wave phases. The generation mechanisms of the equatorial waves and their joint impacts on thermocline mixing remain to be elucidated.
DOI	10.1175/JPO-D-19-0245.1
收录类别	SCI
语种	英语
资助项目	Strategic Priority Research Program[XDA19060102] ; Strategic Priority Research Program[XDB42000000] ; Key Research Program of Frontier Sciences of Chinese Academy of Sciences (CAS)[QYZDB-SSW-DQC030] ; National Natural Science Foundation of China[41976012] ; National Natural Science Foundation of China[Y72143101B] ; National Natural Science Foundation of China[41730534] ; National Natural Science Foundation of China[41622601] ; National Natural Science Foundation of China[91858201] ; Aoshan Talents Program QNML[2017ASTCP-ES03] ; National Science Foundation[OCE-1851520] ; StateKey Laboratory ofMarine Environmental Science (Xiamen University)
WOS研究方向	Oceanography
WOS类目	Oceanography
WOS记录号	WOS:000589826300007
出版者	AMER METEOROLOGICAL SOC
WOS关键词	FREQUENCY INTERNAL WAVES ; TROPICAL INSTABILITY WAVE ; DEEP-CYCLE TURBULENCE ; LARGE-EDDY SIMULATION ; ROSSBY-GRAVITY WAVES ; DIURNAL CYCLE ; INERTIA-GRAVITY ; TRAPPED WAVES ; FINE-SCALE ; SEA-LEVEL
引用统计
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/169416
通讯作者	Liu, Chuanyu
作者单位	1.Chinese Acad Sci, Inst Oceanol, CAS Key Lab Ocean Circulat & Waves, Qingdao, Peoples R China 2.Chinese Acad Sci, Marine Dynam Proc & Climate Funct Lab, Pilot Natl Lab Marine Sci & Technol Qingdao, Qingdao, Peoples R China 3.Chinese Acad Sci, Ctr Ocean Megasci, Qingdao, Peoples R China 4.Univ Chinese Acad Sci, Beijing, Peoples R China 5.Xiamen Univ, Coll Ocean & Earth Sci, State Key Lab Marine Environm Sci, Xiamen, Peoples R China 6.Xiamen Univ, Coll Ocean & Earth Sci, Dept Phys Oceanog, Xiamen, Peoples R China 7.Univ Hamburg, Inst Oceanog, Hamburg, Germany 8.Oregon State Univ, Coll Earth Ocean & Atmospher Sci, Corvallis, OR 97331 USA
推荐引用方式 GB/T 7714	Liu, Chuanyu,Wang, Xiaowei,Liu, Zhiyu,et al. On the Formation of a Subsurface Weakly Sheared Laminar Layer and an Upper Thermocline Strongly Sheared Turbulent Layer in the Eastern Equatorial Pacific: Interplays of Multiple-Time-Scale Equatorial Waves[J]. JOURNAL OF PHYSICAL OCEANOGRAPHY,2020,50(10):2907-2930.
APA	Liu, Chuanyu,Wang, Xiaowei,Liu, Zhiyu,Koehl, Armin,Smyth, William D.,&Wang, Fan.(2020).On the Formation of a Subsurface Weakly Sheared Laminar Layer and an Upper Thermocline Strongly Sheared Turbulent Layer in the Eastern Equatorial Pacific: Interplays of Multiple-Time-Scale Equatorial Waves.JOURNAL OF PHYSICAL OCEANOGRAPHY,50(10),2907-2930.
MLA	Liu, Chuanyu,et al."On the Formation of a Subsurface Weakly Sheared Laminar Layer and an Upper Thermocline Strongly Sheared Turbulent Layer in the Eastern Equatorial Pacific: Interplays of Multiple-Time-Scale Equatorial Waves".JOURNAL OF PHYSICAL OCEANOGRAPHY 50.10(2020):2907-2930.