DOI: 10.1175/2011JCLI4245.1
Scopus记录号: 2-s2.0-84856954689
论文题名: Precise calculations of the existence of multiple AMOC equilibria in coupled climate models. Part I: Equilibrium states
作者: Sijp W.P. ; England M.H. ; Gregory J.M.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2012
卷: 25, 期: 1 起始页码: 282
结束页码: 298
语种: 英语
Scopus关键词: Antarctic intermediate waters
; Competing effects
; Coupled climate model
; Coupled models
; Equilibrium state
; Evolution equations
; Meridional overturning circulations
; Non-linear response
; Nonlinear behavior
; North Atlantic Deep Water
; Ocean climate models
; Salinity
; Salinity gradients
; Salt flux
; South Atlantic
; Southern Ocean
; Stable state
; State behavior
; State parameters
; Steady state solution
; Transient behavior
; Cytology
; Salinity measurement
; Climate models
; Antarctic Intermediate Water
; atmosphere-ocean coupling
; climate forcing
; climate modeling
; computer simulation
; meridional circulation
; North Atlantic Deep Water
; numerical model
; precision
; salinity
; steady-state equilibrium
; Atlantic Ocean
; Atlantic Ocean (South)
; Southern Ocean
英文摘要: This study examines criteria for the existence of two stable states of the Atlantic Meridional OverturningCirculation (AMOC) using a combination of theory and simulations from a numerical coupled atmosphere- ocean climate model. By formulating a simple collection of state parameters and their relationships, the authors reconstruct the North Atlantic Deep Water (NADW) OFF state behavior under a varying external salt-flux forcing. This part (Part I) of the paper examines the steady-state solution, which gives insight into the mechanisms that sustain the NADWOFF state in this coupled model; Part II deals with the transient behavior predicted by the evolution equation. The nonlinear behavior of the Antarctic Intermediate Water (AAIW) reverse cell is critical to the OFF state. Higher Atlantic salinity leads both to a reduced AAIW reverse cell and to a greater vertical salinity gradient in the South Atlantic. The former tends to reduce Atlantic salt export to the Southern Ocean, while the latter tends to increases it. These competing effects produce a nonlinear response of Atlantic salinity and salt export to salt forcing, and the existence of maxima in these quantities. Thus the authors obtain a natural and accurate analytical saddle-node condition for the maximal surface salt flux for which a NADW OFF state exists. By contrast, the bistability indicator proposed byDeVries andWeber does not generallywork in this model. It is applicable only when the effect of theAAIW reverse cell on the Atlantic salt budget is weak. © 2012 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/52623
Appears in Collections: 气候变化事实与影响
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作者单位: Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia; NCAS-Climate, University of Reading, Met Office Hadley Centre, Exeter, United Kingdom
Recommended Citation:
Sijp W.P.,England M.H.,Gregory J.M.. Precise calculations of the existence of multiple AMOC equilibria in coupled climate models. Part I: Equilibrium states[J]. Journal of Climate,2012-01-01,25(1)