DOI: 10.5194/cp-10-487-2014
Scopus记录号: 2-s2.0-84896904461
论文题名: Assessing the impact of laurentide ice sheet topography on glacial climate
作者: Ullman D.J. ; Legrande A.N. ; Carlson A.E. ; Anslow F.S. ; Licciardi J.M.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2014
卷: 10, 期: 2 起始页码: 487
结束页码: 507
语种: 英语
Scopus关键词: air temperature
; albedo
; boundary condition
; climate conditions
; climate modeling
; climate variation
; Last Glacial Maximum
; Laurentide Ice Sheet
; meridional circulation
; Northern Hemisphere
; paleoclimate
; reconstruction
; topography
; Asia
; Pacific Ocean
; Pacific Ocean (North)
英文摘要: Simulations of past climates require altered boundary conditions to account for known shifts in the Earth system. For the Last Glacial Maximum (LGM) and subsequent deglaciation, the existence of large Northern Hemisphere ice sheets caused profound changes in surface topography and albedo. While ice-sheet extent is fairly well known, numerous conflicting reconstructions of ice-sheet topography suggest that precision in this boundary condition is lacking. Here we use a high-resolution and oxygen-isotope-enabled fully coupled global circulation model (GCM) (GISS ModelE2-R), along with two different reconstructions of the Laurentide Ice Sheet (LIS) that provide maximum and minimum estimates of LIS elevation, to assess the range of climate variability in response to uncertainty in this boundary condition. We present this comparison at two equilibrium time slices: the LGM, when differences in ice-sheet topography are maximized, and 14 ka, when differences in maximum ice-sheet height are smaller but still exist. Overall, we find significant differences in the climate response to LIS topography, with the larger LIS resulting in enhanced Atlantic Meridional Overturning Circulation and warmer surface air temperatures, particularly over northeastern Asia and the North Pacific. These up-and downstream effects are associated with differences in the development of planetary waves in the upper atmosphere, with the larger LIS resulting in a weaker trough over northeastern Asia that leads to the warmer temperatures and decreased albedo from snow and sea-ice cover. Differences between the 14 ka simulations are similar in spatial extent but smaller in magnitude, suggesting that climate is responding primarily to the larger difference in maximum LIS elevation in the LGM simulations. These results suggest that such uncertainty in ice-sheet boundary conditions alone may significantly impact the results of paleoclimate simulations and their ability to successfully simulate past climates, with implications for estimating climate sensitivity to greenhouse gas forcing utilizing past climate states. © 2014 Author (s). 资助项目: NSF, National Science Foundation
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49298
Appears in Collections: 气候变化与战略
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Recommended Citation:
Ullman D.J.,Legrande A.N.,Carlson A.E.,et al. Assessing the impact of laurentide ice sheet topography on glacial climate[J]. Climate of the Past,2014-01-01,10(2)