DOI: 10.5194/tc-10-1799-2016
Scopus记录号: 2-s2.0-85016431760
论文题名: A simple equation for the melt elevation feedback of ice sheets
作者: Levermann A ; , Winkelmann R
刊名: Cryosphere
ISSN: 19940416
出版年: 2016
卷: 10, 期: 4 起始页码: 1799
结束页码: 1807
语种: 英语
英文关键词: air temperature
; elevation
; feedback mechanism
; ice sheet
; mass balance
; melt
; numerical model
; sea level change
; threshold
; warming
; Arctic
; Greenland
; Greenland Ice Sheet
英文摘要: In recent decades, the Greenland Ice Sheet has been losing mass and has thereby contributed to global sealevel rise. The rate of ice loss is highly relevant for coastal protection worldwide. The ice loss is likely to increase under future warming. Beyond a critical temperature threshold, a meltdown of the Greenland Ice Sheet is induced by the self-enforcing feedback between its lowering surface elevation and its increasing surface mass loss: the more ice that is lost, the lower the ice surface and the warmer the surface air temperature, which fosters further melting and ice loss. The computation of this rate so far relies on complex numerical models which are the appropriate tools for capturing the complexity of the problem. By contrast we aim here at gaining a conceptual understanding by deriving a purposefully simple equation for the self-enforcing feedback which is then used to estimate the melt time for different levels of warming using three observable characteristics of the ice sheet itself and its surroundings. The analysis is purely conceptual in nature. It is missing important processes like ice dynamics for it to be useful for applications to sea-level rise on centennial timescales, but if the volume loss is dominated by the feedback, the resulting logarithmic equation unifies existing numerical simulations and shows that the melt time depends strongly on the level of warming with a critical slowdown near the threshold: the median time to lose 10% of the present-day ice volume varies between about 3500 years for a temperature level of 0.5 °C above the threshold and 500 years for 5 °C. Unless future observations show a significantly higher melting sensitivity than currently observed, a complete meltdown is unlikely within the next 2000 years without significant ice-dynamical contributions. © Author(s) 2016. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75202
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: Potsdam Institute for Climate Impact Research, Potsdam, Germany; LDEO, Columbia UniversityNY, United States; Institute of Physics, Potsdam University, Potsdam, Germany
Recommended Citation:
Levermann A,, Winkelmann R. A simple equation for the melt elevation feedback of ice sheets[J]. Cryosphere,2016-01-01,10(4)