Seasonal-to-Interannual Time-Scale Dynamics of the Equatorial Undercurrent in the Indian Ocean

CORC > 南海海洋研究所 > 中国科学院南海海洋研究所 > 热带海洋环境国家重点实验室(LTO)

	Seasonal-to-Interannual Time-Scale Dynamics of the Equatorial Undercurrent in the Indian Ocean
	Chen, Gengxin; Han, Weiqing; Li, Yuanlong; Wang, Dongxiao; McPhaden, Michael J.
刊名	JOURNAL OF PHYSICAL OCEANOGRAPHY
	2015
卷号	45 期号:6 页码:1532-1553
关键词	Circulation Dynamics Dynamics Kelvin waves Ocean circulation Ocean dynamics Rossby waves
通讯作者	dxwang@scsio.ac.cn
中文摘要	This paper investigates the structure and dynamics of the Equatorial Undercurrent (EUC) of the Indian Ocean by analyzing in situ observations and reanalysis data and performing ocean model experiments using an ocean general circulation model and a linear continuously stratified ocean model. The results show that the EUC regularly occurs in each boreal winter and spring, particularly during February and April, consistent with existing studies. The EUC generally has a core depth near the 20 degrees C isotherm and can be present across the equatorial basin. The EUC reappears during summer-fall of most years, with core depth located at different longitudes and depths. In the western basin, the EUC results primarily from equatorial Kelvin and Rossby waves directly forced by equatorial easterly winds. In the central and eastern basin, however, reflected Rossby waves from the eastern boundary play a crucial role. While the first two baroclinic modes make the largest contribution, intermediate modes 3-8 are also important. The summer-fall EUC tends to occur in the western basin but exhibits obvious interannual variability in the eastern basin. During positive Indian Ocean dipole (IOD) years, the eastern basin EUC results largely from Rossby waves reflected from the eastern boundary, with directly forced Kelvin and Rossby waves also having significant contributions. However, the eastern basin EUC disappears during negative IOD and normal years because westerly wind anomalies force a westward pressure gradient force and thus westward subsurface current, which cancels the eastward subsurface flow induced by eastern boundary-reflected Rossby waves. Interannual variability of zonal equatorial wind that drives the EUC variability is dominated by the zonal sea surface temperature (SST) gradients associated with IOD and is much less influenced by equatorial wind associated with Indian monsoon rainfall strength.
学科主题	Oceanography
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/15082]
专题	南海海洋研究所_热带海洋环境国家重点实验室(LTO)
推荐引用方式 GB/T 7714	Chen, Gengxin,Han, Weiqing,Li, Yuanlong,et al. Seasonal-to-Interannual Time-Scale Dynamics of the Equatorial Undercurrent in the Indian Ocean[J]. JOURNAL OF PHYSICAL OCEANOGRAPHY,2015,45(6):1532-1553.
APA	Chen, Gengxin,Han, Weiqing,Li, Yuanlong,Wang, Dongxiao,&McPhaden, Michael J..(2015).Seasonal-to-Interannual Time-Scale Dynamics of the Equatorial Undercurrent in the Indian Ocean.JOURNAL OF PHYSICAL OCEANOGRAPHY,45(6),1532-1553.
MLA	Chen, Gengxin,et al."Seasonal-to-Interannual Time-Scale Dynamics of the Equatorial Undercurrent in the Indian Ocean".JOURNAL OF PHYSICAL OCEANOGRAPHY 45.6(2015):1532-1553.