气候变化领域集成服务门户(CCPortal): Surface constraints on the depth of the Atlantic meridional overturning circulation: Southern Ocean versus North Atlantic

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DOI	10.1175/JCLI-D-19-0546.1
	Surface constraints on the depth of the Atlantic meridional overturning circulation: Southern Ocean versus North Atlantic
	Sun S.; Eisenman I.; Zanna L.; Stewart A.L.
发表日期	2020
ISSN	0894-8755
起始页码	3125
结束页码	3149
卷号	33 期号:8
英文摘要	Paleoclimate proxy evidence suggests that the Atlantic meridional overturning circulation (AMOC) was about 1000 m shallower at the Last Glacial Maximum (LGM) compared to the present. Yet it remains unresolved what caused this glacial shoaling of the AMOC, and many climate models instead simulate a deeper AMOC under LGM forcing. While some studies suggest that Southern Ocean surface buoyancy forcing controls the AMOC depth, others have suggested alternatively that North Atlantic surface forcing or interior diabatic mixing plays the dominant role. To investigate the key processes that set the AMOC depth, here we carry out a number of MITgcm ocean-only simulations with surface forcing fields specified from the simulation results of three coupled climate models that span much of the range of glacial AMOC depth changes in phase 3 of the Paleoclimate Model Intercomparison Project (PMIP3). We find that the MITgcm simulations successfully reproduce the changes in AMOC depth between glacial and modern conditions simulated in these three PMIP3 models. By varying the restoring time scale in the surface forcing, we show that the AMOC depth is more strongly constrained by the surface density field than the surface buoyancy flux field. Based on these results, we propose a mechanism by which the surface density fields in the high latitudes of both hemispheres are connected to the AMOC depth. We illustrate the mechanism using MITgcm simulations with idealized surface forcing perturbations as well as an idealized conceptual geometric model. These results suggest that the AMOC depth is largely determined by the surface density fields in both the North Atlantic and the Southern Ocean. © 2020 American Meteorological Society. All rights reserved.
英文关键词	Buoyancy; Climate models; Glacial geology; Atlantic meridional overturning circulations; Coupled climate model; Geometric modeling; Last Glacial Maximum; Model inter comparisons; Paleoclimate proxy; Surface buoyancy flux; Surface constraints; Oceanography; buoyancy forcing; climate modeling; diabatic process; geometry; Last Glacial Maximum; meridional circulation; overturn; paleoclimate; shoaling wave; Atlantic Ocean; Atlantic Ocean (North); Southern Ocean
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/171352
作者单位	Scripps Institution of Oceanography, University of California, San Diego, San Diego, CA, United States; Department of Physics, University of Oxford, Oxford, United Kingdom, Courant Institute of Mathematical Sciences, New York University, New York, NY, United States; Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, CA, United States
推荐引用方式 GB/T 7714	Sun S.,Eisenman I.,Zanna L.,et al. Surface constraints on the depth of the Atlantic meridional overturning circulation: Southern Ocean versus North Atlantic[J],2020,33(8).
APA	Sun S.,Eisenman I.,Zanna L.,&Stewart A.L..(2020).Surface constraints on the depth of the Atlantic meridional overturning circulation: Southern Ocean versus North Atlantic.Journal of Climate,33(8).
MLA	Sun S.,et al."Surface constraints on the depth of the Atlantic meridional overturning circulation: Southern Ocean versus North Atlantic".Journal of Climate 33.8(2020).