Cite this paper:
PENG Hanbang, PAN Aijun, ZHENG Quan'an, HU Jianyu. Analysis of monthly variability of thermocline in the South China Sea[J]. HaiyangYuHuZhao, 2018, 36(2): 205-215

Analysis of monthly variability of thermocline in the South China Sea

PENG Hanbang1,2, PAN Aijun2, ZHENG Quan'an3, HU Jianyu1
1 State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China;
2 Ocean Dynamics Laboratory, the Third Institute of Oceanography, State Oceanic Administration(SOA), Xiamen 361005, China;
3 Department of Atmospheric and Oceanic Science, University of Maryland, College Park 20742, USA
Abstract:
This study analyzes monthly variability of thermocline and its mechanism in the South China Sea (SCS). The study is based on 51-year (1960-2010) monthly seawater temperature and surface wind stress data from Simple Ocean Data Assimilation (SODA), together with heat flux, precipitation and evaporation data from the National Centers for Environmental Prediction (NCEP), the National Oceanic and Atmospheric Administration (NOAA) and the Woods Hole Oceanographic Institution, respectively. The results reveal that the upper boundary depth (Zup), lower boundary depth (Zlow), thickness (△Z) and intensity (Tz) of thermocline in the SCS show remarkable monthly variability. Being averaged for the deep basin of SCS, Zup deepens gradually from May to the following January and then shoals from February to May, while Zlow varies little throughout the whole year. Further diagnostics indicates that the monthly variability of Zup is mainly caused by the buoyancy flux and wind stress curl. Using a linear method, the impacts of the buoyancy flux and wind stress curl on Zup can be quantitatively distinguished. The results suggest that Zup tends to deepen about 4.6 m when the buoyancy flux increases by 1×10-5 kg/(m·s3), while it shoals about 2.5 m when the wind stress curl strengthens by 1×10-7 N/m3.
Key words:    South China Sea|thermocline|upper boundary depth|buoyancy flux|wind stress curl   
Received: 2016-05-25   Revised:
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