DOI: 10.1175/JCLI-D-17-0559.1
Scopus记录号: 2-s2.0-85047074236
论文题名: Fast physics and slow physics in the nonlinear Dansgaard-Oeschger relaxation oscillation
作者: Vettoretti G. ; Peltier W.R.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2018
卷: 31, 期: 9 起始页码: 3423
结束页码: 3449
语种: 英语
英文关键词: Atmosphere-ocean interaction
; Climate change
; Climate variability
; Coupled models
; Paleoclimate
; Sea ice
Scopus关键词: Atmospheric thermodynamics
; Budget control
; Climate models
; Oceanography
; Relaxation oscillators
; Sea ice
; Stability
; Water
; Atmosphere-ocean interactions
; Climate variability
; Convective instabilities
; Coupled models
; East greenland currents
; North atlantic deep water formations
; Paleoclimates
; Relaxation oscillation
; Climate change
英文摘要: The Dansgaard-Oeschger (D-O) relaxation oscillation that governed glacial climate variability during marine isotope stage 3 has been accurately simulated using a high-resolution coupled climate model. Here the authors present additional detailed analyses of both the slow physics transition between warm and cold states and the fast physics transition between cold and warm states of the D-O cycle. First, the authors demonstrate that the mechanisms active during the slow transition from interstadial to stadial conditions involves the continuous flux of thick and old sea ice from the Arctic basin into the North Atlantic subpolar gyre region along the East Greenland Current. During this slow physical process, the freshwater input from sea ice melting as it moves over the surface of the warm ocean restratifies the high-latitude North Atlantic and leads to a significant reduction in the rate of North Atlantic Deep Water formation. A detailed freshwater budget and hydrography analysis is also presented to demonstrate that the D-O cycle is a low-latitude-high-latitude salt oscillator as the authors have previously argued. Second, the authors provide a more detailed analysis than previously of the fast-time-scale processes that govern the extremely rapid transition from cold stadial conditions back to the warm interstadial state. These are associated with the onset of a sub-sea ice thermohaline convective instability, which opens a massive polynya to the north of the southern boundary of the extensive North Atlantic sea ice lid that is characteristic of stadial conditions. This instability is enabled by the continuous increase of salinity above the sub-sea ice pycnocline, which eliminates the vertical salinity gradient that prevents convective destabilization of the water column under full stadial conditions. This reduction in the vertical salinity gradient beneath the sea ice lid results from the continuing northward salt transport by the North Atlantic gyre circulation once the expansion of the stadial sea ice lid has ceased. The onset of instability occurs in the Irminger basin to the south of Denmark Strait, and the authors discuss the reason for this localization of instability onset. © 2018 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/111565
Appears in Collections: 气候减缓与适应
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作者单位: Department of Physics, University of Toronto, Toronto, ON, Canada
Recommended Citation:
Vettoretti G.,Peltier W.R.. Fast physics and slow physics in the nonlinear Dansgaard-Oeschger relaxation oscillation[J]. Journal of Climate,2018-01-01,31(9)