Persistent mixing bursts in the equatorial Pacific thermocline induced by persistent equatorial waves

Jingjing ZHANG; Chuanyu LIU; Xiang GONG; Fan WANG

doi:10.1007/s00343-023-2350-z

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Persistent mixing bursts in the equatorial Pacific thermocline induced by persistent equatorial waves

Physics | Updated：2024-10-11

- Persistent mixing bursts in the equatorial Pacific thermocline induced by persistent equatorial waves
- Journal of Oceanology and Limnology Vol. 42, Issue 2, Pages: 492-510(2024)
- Affiliations：
  
  1.School of Mathematics and Physics, Qingdao University of Science and Technology, Qingdao 266100, China
  2.Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
  3.Laoshan Laboratory, Qingdao 266237, China
- Author bio：
  
  chuanyu.liu@qdio.ac.cn
- Funds：
- DOI：10.1007/s00343-023-2350-z
  CLC：
- Received：24 October 2022，
  
  Online First：05 May 2023，
  
  Published：01 March 2024
- Accepted：
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ZHANG Jingjing,LIU Chuanyu,GONG Xiang,et al.Persistent mixing bursts in the equatorial Pacific thermocline induced by persistent equatorial waves[J].Journal of Oceanology and Limnology,2024,42(02):492-510.
DOI：

ZHANG Jingjing,LIU Chuanyu,GONG Xiang,et al.Persistent mixing bursts in the equatorial Pacific thermocline induced by persistent equatorial waves[J].Journal of Oceanology and Limnology,2024,42(02):492-510. DOI： 10.1007/s00343-023-2350-z.

摘要

Abstract

A recent study by Liu et al. (2020) suggested that due to the saturation of equatorially trapped planetary waves with different dynamical types

temporal periods

meridional and baroclinic modes

complex layer structures of vertical velocity shear and hence turbulent mixing could frequently occur in the thermocline of the eastern equatorial Pacific. We investigated the occurrence of the interior turbulent mixing as indicated by shear instabilities

above the Equatorial Undercurrent (EUC) core at three equatorial sites along 140°W

170°W

and 165°‍E

respectively

based mainly on data from the Tropical Atmosphere and Ocean (TAO) mooring array. We found that turbulent mixing bursts persisted in the thermocline of all three sites. Specifically

the interior turbulent mixing layers (ITMLs) could occur in probability of approximately 68%

53%

and 48% at the three sites

respectively. The overall occurrence probability shows obvious and similar biannual variations at 140°W and 170°W

which is higher in boreal from late summer to winter and lower in spring. Vertically

the ITMLs are primarily located above the EUC core and prevail in deeper (shallower) layers from late summer to winter (spring). Most ITMLs (70%) lasted for hours to 3 days

and a few of them (15%) for more than 7 days. The thicknesses of ITMLs were concentrated between 15 and 55 m. At 165°‍E

the vertical distribution of ITML occurrence probability was different from that at 140°W and 170°W

as it did not show a preference for depths; the durations of ITMLs are short (also from hours to several days) and their thicknesses were between 5 and 25 m. These properties

particularly the high occurrence probability

and short durations demonstrated the persistence of thermocline mixing in the western to eastern equatorial Pacific thermocline and confirmed the generation mechanism by persistent equatorial waves as well.

关键词

Keywords

references

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