Mechanisms of Atlantic Meridional Overturning Circulation （AMOC）Variability in a Coupled Ocean-Atmosphere GCM

The mechanisms involved in the variability of Atlantic Meridional Overturning Circulation （AMOC） are studied using a 2000-yr control simulation of the coupled Fast Ocean-Atmosphere Model （FOAM）.This study identifies a coupled mode between SST and surface heat flux in the North Atlantic at the decada...

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Published in大气科学进展：英文版 Vol. 31; no. 2; pp. 241 - 251
Main Author Boyin HUANG ZHU Jiang YANG Haijun
Format Journal Article
LanguageEnglish
Published 2014
Subjects
GCM
北大西洋
地表热通量
年际时间尺度
机制
海气耦合
环流
翻转
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ISSN0256-1530
1861-9533

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Summary:The mechanisms involved in the variability of Atlantic Meridional Overturning Circulation （AMOC） are studied using a 2000-yr control simulation of the coupled Fast Ocean-Atmosphere Model （FOAM）.This study identifies a coupled mode between SST and surface heat flux in the North Atlantic at the decadal timescale,as well as a forcing mode of surface heat flux at the interannual timescale.The coupled mode is regulated by AMOC through meridional heat transport.The increase in surface heating in the North Atlantic weakens the AMOC approximately 10 yr later,and the weakened AMOC in turn decreases SST and sea surface salinity.The decreased SST results in an increase in surface heating in the North Atlantic,thus forming a positive feedback loop.Meanwhile,the weakened AMOC weakens northward heat transport and therefore lowers subsurface temperature approximately 19 yr later,which prevents the AMOC from weakening.In the forcing mode,the surface heat flux leads AMOC by approximately 4 yr.
Bibliography:Atlantic Meridional Overturning Circulation; AMOC variability; coupled mode; and forcing mode
Boyin HUANG, ZHU Jiang, YANG Haijun（1. National Climatic Data Centez NOAA, Asheville, NC 28801, USA 2Laboratory for Climate and Ocean-Atmosphere Studies, and Department of Atmospheric and Oceanic Sciences School of Physics, Peking University, Beijing 100871）
11-1925/O4
The mechanisms involved in the variability of Atlantic Meridional Overturning Circulation （AMOC） are studied using a 2000-yr control simulation of the coupled Fast Ocean-Atmosphere Model （FOAM）.This study identifies a coupled mode between SST and surface heat flux in the North Atlantic at the decadal timescale,as well as a forcing mode of surface heat flux at the interannual timescale.The coupled mode is regulated by AMOC through meridional heat transport.The increase in surface heating in the North Atlantic weakens the AMOC approximately 10 yr later,and the weakened AMOC in turn decreases SST and sea surface salinity.The decreased SST results in an increase in surface heating in the North Atlantic,thus forming a positive feedback loop.Meanwhile,the weakened AMOC weakens northward heat transport and therefore lowers subsurface temperature approximately 19 yr later,which prevents the AMOC from weakening.In the forcing mode,the surface heat flux leads AMOC by approximately 4 yr.
ISSN:0256-1530
1861-9533