DOI: 10.5194/tc-8-453-2014
Scopus记录号: 2-s2.0-84897846919
论文题名: Decadal trends in the Antarctic sea ice extent ultimately controlled by ice-ocean feedback
作者: Goosse H ; , Zunz V
刊名: Cryosphere
ISSN: 19940416
出版年: 2014
卷: 8, 期: 2 起始页码: 453
结束页码: 470
语种: 英语
英文关键词: climate modeling
; decadal variation
; heat flux
; ice-ocean interaction
; mixing
; sea ice
; timescale
; vertical mixing
; Southern Ocean
英文摘要: The large natural variability of the Antarctic sea ice is a key characteristic of the system that might be responsible for the small positive trend in sea ice extent observed since 1979. In order to gain insight of the processes responsible for this variability, we have analysed in a control simulation performed with a coupled climate model a positive ice-ocean feedback that amplifies sea ice variations. When sea ice concentration increases in a region, in particular close to the ice edge, the mixed layer depth tends to decrease. This can be caused by a net inflow of ice, and thus of freshwater, that stabilizes the water column. A second stabilizing mechanism at interannual timescales is associated with the downward salt transport due to the seasonal cycle of ice formation: brine is released in winter and mixed over a deep layer while the freshwater flux caused by ice melting is included in a shallow layer, resulting in a net vertical transport of salt. Because of this stronger stratification due to the presence of sea ice, more heat is stored at depth in the ocean and the vertical oceanic heat flux is reduced, which contributes to maintaining a higher ice extent. This positive feedback is not associated with a particular spatial pattern. Consequently, the spatial distribution of the trend in ice concentration is largely imposed by the wind changes that can provide the initial perturbation. A positive freshwater flux could alternatively be the initial trigger but the amplitude of the final response of the sea ice extent is finally set up by the amplification related to the ice-ocean feedback. Initial conditions also have an influence as the chance to have a large increase in ice extent is higher if starting from a state characterized by a low value. © Author(s) 2014. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/74876
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Université catholique de Louvain, Earth and Life Institute, Georges Lemaître Centre for Earth and Climate Research, Place Pasteur, 3, 1348 Louvain-la-Neuve, Belgium
Recommended Citation:
Goosse H,, Zunz V. Decadal trends in the Antarctic sea ice extent ultimately controlled by ice-ocean feedback[J]. Cryosphere,2014-01-01,8(2)