Eddy analysis in the subtropical zonal band of the North Pacific Ocean
Eddy analysis in the subtropical zonal band of the North Pacific Ocean
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DOI：
10.1016/j.dsr.2012.06.001
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发表时间：
2012-10-01
影响因子：
2.4
通讯作者：
Nencioli, Francesco
中科院分区：
文献类型：
--
作者：
Liu, Yu;Dong, Changming;Nencioli, Francesco
北太平洋有两个纬向高涡动动能(EKE)带。最高的一个位于黑潮延伸区，第二个位于亚热带地区。本文主要研究的是后者。将一种基于速度矢量几何的涡旋检测方法应用于SSHA地转流，以识别和跟踪涡旋，并生成一个包含涡旋产生、演变和终止的时空信息的涡旋数据集。通过对该数据集的分析，可以对广泛的涡旋参数进行调查。从1993年到2010年，在该波段内产生了大约6000个持续时间超过8周的涡流。所有涡旋都向西移动，气旋性涡旋和反气旋性涡旋分别向北纬21度以南和北纬21度以北偏南。从统计数据来看，涡旋的生命周期可分为三个不同的阶段：前五分之一对应于生长期；后五分之三对应于稳定期；后五分之一对应于衰退期。利用在探测到的涡区内观测到的ARGO垂直剖面，研究了温跃层和盐跃层在涡旋作用下的垂直位移。从海温资料得到的锋面强度被用来解释在纬向带内调制时空涡旋变化的机制。(C)2012爱思唯尔有限公司。保留所有权利。
There are two zonal bands of eminently high eddy kinetic energy (EKE) in the North Pacific Ocean. The highest one is located in the Kuroshio Extension and the second one is in the subtropical area. This paper focuses on the latter. An eddy detection scheme based on velocity vector geometry is applied to the SSHA-derived geostrophic currents to identify and track eddies, and to generate an eddy dataset which includes spatial and temporal information on eddy generation, evolution and termination. Analysis of this dataset allowed the investigation of a broad range of eddy parameters. From 1993 to 2010, about six thousand eddies with lifetime longer than eight weeks were generated within the band. All eddies moved westward, and both cyclonic and anticyclonic eddies deflected northward south of 21 degrees N and southward north of 21 degrees N, respectively. Statistically, three different stages of an eddy's lifetime can be identified: the first one-fifth of its lifetime corresponds to the growing period; the successive three-fifths after that to its stable stage; the last one-fifth to its decaying period. Observed Argo vertical profiles collected within the detected eddy areas are used to investigate the eddy-induced vertical displacement of the thermocline and the halocline. Frontal intensity derived from the SST data is used to explain the mechanism modulating temporal and spatial eddy variations within the zonal band. (c) 2012 Elsevier Ltd. All rights reserved.