title: Observed deep energetic eddies by seamount wake.
abstract: Despite numerous surface eddies are observed in the ocean, deep eddies (a type of eddies which have no footprints at the sea surface) are much less reported in the literature due to the scarcity of their observation. In this letter, from recently collected current and temperature data by mooring arrays, a deep energetic and baroclinic eddy is detected in the northwestern South China Sea (SCS) with its intensity, size, polarity and structure being characterized. It remarkably deepens isotherm at deep layers by the amplitude of ~120 m and induces a maximal velocity amplitude about 0.18 m/s, which is far larger than the median velocity (0.02 m/s). The deep eddy is generated in a wake when a steering flow in the upper layer passes a seamount, induced by a surface cyclonic eddy. More observations suggest that the deep eddy should not be an episode in the area. Deep eddies significantly increase the velocity intensity and enhance the mixing in the deep ocean, also have potential implication for deep-sea sediments transport.
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Gengxin
authors.initials: G
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Dongxiao
authors.initials: D
authors.lastname: Wang
authors.affiliation: Marine Science College, University of Information Science and Technology, Nanjing, China.|Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, USA.
authors.forename: Changming
authors.initials: C
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zu
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.|School of Marine Sciences, University of Maine, Orono, Maine, USA.
authors.forename: Huijie
authors.initials: H
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Yeqiang
authors.initials: Y
authors.lastname: Shu
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Yiquan
authors.initials: Y
authors.lastname: Qi
authors.affiliation: Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, Faculty of Resources, China University of Geosciences, Wuhan, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen