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

作　　者：XIE Qiang XIAO JinGen WANG DongXiao YU YongQiang 

机构地区：[1]State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences [2]Sanya Institute of Deep Sea Science and Engineering,Chinese Academy of Sciences [3]University of the Chinese Academy of Sciences [4]State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences

出　　处：《Chinese Science Bulletin》2013年第32期4000-4011,共12页

基　　金：supported by the National Basic Research Program of China(41276024 and 41276024);the Knowledge Innovation Engineering Frontier Project of Sanya Institute of Deep Sea Science and Engineering(SIDSSE-201205);Sanya and Chinese Academy of Sciences Cooperation Project(2012YD01)

摘　　要：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.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 circula- tions, which may provide a reference for future model improvement.

关 键 词：海洋模型 环流分析 输出结果 中国南海 海深 底层 数字环境模型 评估模型 

分 类 号：P731.1[天文地球—海洋科学]