Simulation and future projection of the mixed layer depth and subduction process in the subtropical Southeast Pacific

Ruibin Xia; Yijun He; Tingting Yang

doi:10.1007/s13131-021-1877-0

Volume 40 Issue 12

Dec. 2022

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Ruibin Xia, Yijun He, Tingting Yang. Simulation and future projection of the mixed layer depth and subduction process in the subtropical Southeast Pacific[J]. Acta Oceanologica Sinica, 2021, 40(12): 104-113. doi: 10.1007/s13131-021-1877-0

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Ruibin Xia, Yijun He, Tingting Yang. Simulation and future projection of the mixed layer depth and subduction process in the subtropical Southeast Pacific[J]. Acta Oceanologica Sinica, 2021, 40(12): 104-113. doi: 10.1007/s13131-021-1877-0

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Simulation and future projection of the mixed layer depth and subduction process in the subtropical Southeast Pacific

doi: 10.1007/s13131-021-1877-0

Ruibin Xia^{1, 2},
Yijun He^{1, 3
,
,},
Tingting Yang^{4, 5, 6, 7}

1.
School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing 210044, China
2.
MNR Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136, China
3.
Laboratory for Regional Oceanography and Numerical Modeling, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
4.
Key Laboratory of Meteorological Disaster, Ministry of Education, Nanjing 210044, China
5.
Joint International Research Laboratory of Climate and Environment Change, Nanjing 210044, China
6.
Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing 210044, China
7.
Nanjing Joint Institute for Atmospheric Sciences, Nanjing 210008, China

Funds: The National Natural Science Foundation of China under contract Nos 41606217 and 41620104003; the Open Fund of Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, under contract No. KP201702; the Open Fund of the Key Laboratory of Ocean Circulation and Waves, Chinese Academy of Sciences, under contract No. KLOCW1903.

More Information

Corresponding author: E-mail: yjhe@nuist.edu.cn
Received Date: 2021-03-20
Accepted Date: 2021-06-15

Available Online: 2021-09-03

Publish Date: 2021-11-25

Abstract

Abstract

The present climate simulation and future projection of the mixed layer depth (MLD) and subduction process in the subtropical Southeast Pacific are investigated based on the geophysical fluid dynamics laboratory earth system model (GFDL-ESM2M). The MLD deepens from May and reaches its maximum (>160 m) near (24°S, 104°W) in September in the historical simulation. The MLD spatial pattern in September is non-uniform in the present climate, which shows three characteristics: (1) the deep MLD extends from the Southeast Pacific to the West Pacific and leads to a “deep tongue” until 135°W; (2) the northern boundary of the MLD maximum is smoothly near 18°S, and MLD shallows sharply to the northeast; (3) there is a relatively shallow MLD zone inserted into the MLD maximum eastern boundary near (26°S, 80°W) as a weak “shallow tongue”. The MLD non-uniform spatial pattern generates three strong MLD fronts respectively in the three key regions, promoting the subduction rate. After global warming, the variability of MLD spatial patterns is remarkably diverse, rather than deepening consistently. In all the key regions, the MLD deepens in the south but shoals in the north, strengthing the MLD front. As a result, the subduction rate enhances in these areas. This MLD antisymmetric variability is mainly influenced by various factors, especially the potential-density horizontal advection non-uniform changes. Notice that the freshwater flux change helps to deepen the MLD uniformly in the whole basin, so it hardly works on the regional MLD variability. The study highlights that there are regional differences in the mechanisms of the MLD change, and the MLD front change caused by MLD non-uniform variability is the crucial factor in the subduction response to global warming.
- mixed layer depth,
- mixed layer depth front,
- subduction,
- ocean potential-density advection

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References(30)

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