Wind effect on the Atlantic meridional overturning circulation via sea ice and vertical diffusion

Effects of wind and fresh water on the Atlantic meridional overturning circulation (AMOC) are investigated using a fully coupled climate model. The AMOC can change significantly when perturbed by either wind stress or freshwater flux in the North Atlantic. This study focuses on wind stress effect. O...

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Bibliographic Details
Published in:Climate Dynamics
Main Authors: Yang, Haijun, Wang, Kun, Dai, Haijin, Wang, Yuxing, Li, Qing
Other Authors: Yang, HJ (reprint author), Peking Univ, Lab Climate & Ocean Atmosphere Studies LaCOAS, 209 Chengfu Rd, Beijing 100871, Peoples R China.; Yang, HJ (reprint author), Peking Univ, Sch Phys, Dept Atmospher & Ocean Sci, 209 Chengfu Rd, Beijing 100871, Peoples R China., Peking Univ, Lab Climate & Ocean Atmosphere Studies LaCOAS, 209 Chengfu Rd, Beijing 100871, Peoples R China., Peking Univ, Sch Phys, Dept Atmospher & Ocean Sci, 209 Chengfu Rd, Beijing 100871, Peoples R China., Yang, HJ (reprint author), Peking Univ, Sch Phys, Dept Atmospher & Ocean Sci, 209 Chengfu Rd, Beijing 100871, Peoples R China.
Format: Journal/Newspaper
Language:English
Published: CLIMATE DYNAMICS 2016
Subjects:
AMOC
Wind effect
Freshwater flux
Sea ice
Vertical diffusion
Positive feedback
NORTH-ATLANTIC
THERMOHALINE CIRCULATION
FRESH-WATER
SOUTHERN-OCEAN
DEEP-WATER
MULTIDECADAL OSCILLATION
CLIMATE VARIABILITY
MODEL
IMPACT
TEMPERATURE
Southern Ocean
North Atlantic
North atlantic Thermohaline circulation
Online Access:https://hdl.handle.net/20.500.11897/492194
https://doi.org/10.1007/s00382-015-2774-z
Description
Summary:Effects of wind and fresh water on the Atlantic meridional overturning circulation (AMOC) are investigated using a fully coupled climate model. The AMOC can change significantly when perturbed by either wind stress or freshwater flux in the North Atlantic. This study focuses on wind stress effect. Our model results show that the wind forcing is crucial in maintaining the AMOC. Reducing wind forcing over the ocean can cause immediately weakening of the vertical salinity diffusion and convection in the mid-high latitudes Atlantic, resulting in an enhancement of vertical salinity stratification that restrains the deep water formation there, triggering a slowdown of the thermohaline circulation. As the thermohaline circulation weakens, the sea ice expands southward and melts, providing the upper ocean with fresh water that weakens the thermohaline circulation further. The wind perturbation experiments suggest a positive feedback between sea-ice and thermohaline circulation strength, which can eventually result in a complete shutdown of the AMOC. This study also suggests that sea-ice variability may be also important to the natural AMOC variability on decadal and longer timescales. NSF of China [91337106, 41376007, 41176002, 40976007]; National Basic Research Program of China [2012CB955200] SCI(E) ARTICLE hjyang@pku.edu.cn 11-12 3387-3403 46

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