Analysis of deep-layer and bottom circulations in the South China Sea based on eight quasi-global ocean model outputs

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• 作者：Qiang Xie (1) (3)
  JinGen Xiao (1) (2)
  DongXiao Wang (1)
  YongQiang Yu (4)
  
• 关键词：quasi ; global ocean model ; deep ; layer and bottom SCS circulations ; model evaluation
• 刊名：Chinese Science Bulletin
• 出版年：2013
• 出版时间：November 2013
• 年：2013
• 卷：58
• 期：32
• 页码：4000-4011
• 全文大小：
• 作者单位：Qiang Xie (1) (3)
  JinGen Xiao (1) (2)
  DongXiao Wang (1)
  YongQiang Yu (4)
  
  1. State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
  3. Sanya Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
  2. University of the Chinese Academy of Sciences, Beijing, 100049, China
  4. State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
  
• ISSN：1861-9541

文摘

This study is a preliminary analysis of the South China Sea (SCS) deep circulations using eight quasi-global high-resolution ocean model outputs. The goal is to assess models’ ability to simulate these deep circulations. The analysis reveals that models’ deep temperatures are colder than the observations in the World Ocean Atlas, while most models’ deep salinity values are higher than the observations, indicating models’ deep water is generally colder and saltier than the reality. Moreover, there are long-term trends in both temperature and salinity simulations. The Luzon Strait transport below 1500 m is 0.36 Sv when averaged for all models, smaller compared with the observation, which is about 2.5 Sv. Four assimilated models and one unassimilated (OCCAM) display that the Luzon deep-layer overflow reaches its minimum in spring and its maximum in winter. The vertically integrated streamfunctions below 2400 m from these models show a deep cyclonic circulation in the SCS on a large scale, but the pattern is different from the diagnostic streamfunction from the U.S Navy Generalized Digital Environment Model (GDEM-Version 3.0, GDEMv3). The meridional overturning structure above 1000 m is similar in all models, but the spatial distribution and intensity below 1500 m are quite different from model to model. Moreover, the meridional overturning below 2400 m in these models is weaker than that of the GDEMv3, which indicates a deep vertical mixing process in these models is biased weak. Based on the above evaluation, this paper discusses the impacts of T/S initial value, topography, and mixing scheme on the SCS deep circulations, which may provide a reference for future model improvement.