Journal of Tropical Oceanography >
Mid-depth zonal jets and their characteristics in the tropical Pacific Ocean derived from Argo trajectory
Received date: 2017-01-02
Request revised date: 2017-02-24
Online published: 2017-07-26
Supported by
National Natural Science Foundation of China (41525019, 41521005)
“Global Changes and Air-sea Interaction” of State Oceanic Administration (GASI-IPOVAI-02)
Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11010000)
Copyright
The characteristics and variation of mid-depth zonal jets in the tropical Pacific Ocean are examined using the trajectory of Argo floats. The method to estimate zonal intermediate currents based on Argo trajectory data is more appropriate in the equatorial region because it is free of the restrictions imposed by the methods based on the referenced velocity and Coriolis force. The results indicate that in the equatorial Pacific Ocean, the mid-layer (1000 dbar) zonal jets have a symmetric band-like structure in both Northern and Southern Hemispheres. The strong jets are centered near the equatorial regions, whereas there are several eastward zonal jets in the off-equatorial ocean (9°N, 13°N, 18°N). In addition, the characteristics of temporal variability are relatively complex. In the near-equatorial area, seasonal scale is the major and most important component, while in the off-equatorial region multiple time scale processes dominate. The Rossby wave dynamics and local response probably contribute to this difference.
XIA Yifan , DU Yan , WANG Tianyu , XIE Qiang . Mid-depth zonal jets and their characteristics in the tropical Pacific Ocean derived from Argo trajectory[J]. Journal of Tropical Oceanography, 2017 , 36(4) : 1 -9 . DOI: 10.11978/2017001
Fig. 1 Schematic diagram of depth vs time for an Argo float measuring cycle图1 Argo浮标一个测量循环内浮标深度与时间示意图 T1表示即将下沉时刻, T2表示下沉到滞留深度时刻, T3表示即将离开滞留深度时刻, T4表示到达下潜最大深度时刻, T5表示刚浮上水面时刻, T7表示下一个下沉时刻, Ts1到Tsn代表上浮漂流时同卫星通讯时刻; Tdown表示下沉时间, Tup表示上浮时间, Tasc表示上升测量时间 |
Fig. 2 a) Spatial distribution of Argo floats in the tropical Pacific Ocean (parking at 1000 dbar). The color shading is the number of profiles in 3° longitude × 1° latitude bins. b) Histogram of the Argo float profiles’ number as a function of time with different parking depths图2 Argo浮标剖面在热带太平洋的空间分布(a, 滞留深度为1000dbar)和在不同滞留深度上Argo浮标剖面的数量分布随时间变化直方图(b)填色代 |
Fig. 3 Error estimation: a) surface drifting error distribution estimated from the extrapolation with Argo data; b) vertical shear error distribution calculated from vertical integral with OFES data图3 由Argo数据外推得到的海面漂流误差分布(a)和利用OFES数据垂向积分得到的垂向剪切误差分布(b) |
Fig. 4 a) Mean zonal currents at surface in the tropical Pacific Ocean; b) mean zonal currents at surface, zonally averaged in the 130°E-80°W band; c) mean zonal currents at 1000 dbar in the tropical Pacific Ocean; d) mean zonal currents at 1000 dbar, zonally averaged in the 130°E-80°W band图4 热带太平洋表层纬向流速(a)和表层130°E—80°W纬向速度的纬向平均(b), 以及热带太平洋1000dbar层纬向流速(c)和1000dbar层130°E—80°W纬向速度的纬向平均(d) |
Fig. 5 a) Surface EKE (eddy kinetic energy) (GLD); b) 1000dbar EKE (Argo)图5 表层的涡动能(a, GLD数据)和1000dbar深度上的涡动能(b, Argo数据) |
Fig. 6 The four seasonal anomalies (seasonal mean removed) of zonal currents at 1000 dbar estimated from Argo data (a-d), and the corresponding data using OFES output (e-h)图6 1000dbar深度上4条东向流动的纬向平均流场异常(a—d)的季节变化以及对应的OFES模式数据(e—h) a、e: 0°N—2°N; b、f: 8°N—10°N; c、g: 12°N—14°N; d、h: 17°N—19°N |
Fig. 7 Power spectrum of four eastward mean zonal flows at 1000 dbar图7 1000dbar深度上4条东向平均纬向流动的功率谱分析 a. 0°N—2°N; b. 8°N—10°N; c. 12°N—14°N; d. 17°N—19°N; 红线代 |
The authors have declared that no competing interests exist.
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