DOI: 10.1016/j.epsl.2018.05.006
Scopus记录号: 2-s2.0-85048716050
论文题名: Wave inhibition by sea ice enables trans-Atlantic ice rafting of debris during Heinrich events
作者: Wagner T.J.W. ; Dell R.W. ; Eisenman I. ; Keeling R.F. ; Padman L. ; Severinghaus J.P.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 495 起始页码: 157
结束页码: 163
语种: 英语
英文关键词: Heinrich events
; ice-rafted debris
; icebergs
; melt water
; modeling
Scopus关键词: Climate models
; Debris
; Glacial geology
; Models
; Ocean currents
; Sedimentation
; Sediments
; Surface waters
; Climate model simulations
; Heinrich Events
; Ice rafted debris
; icebergs
; Lagrangian particles
; Laurentide ice sheets
; Melt water
; Sea surface temperature (SST)
; Sea ice
; climate modeling
; Heinrich event
; ice-rafted debris
; iceberg
; Last Glacial Maximum
; meltwater
; modeling
; ocean wave
; paleoclimate
; sea ice
; Atlantic Ocean
英文摘要: The last glacial period was punctuated by episodes of massive iceberg calving from the Laurentide Ice Sheet, called Heinrich events, which are identified by layers of ice-rafted debris (IRD) in ocean sediment cores from the North Atlantic. The thickness of these IRD layers declines more gradually with distance from the iceberg sources than would be expected based on present-day iceberg drift and decay. Here we model icebergs as passive Lagrangian particles driven by ocean currents, winds, and sea surface temperatures. The icebergs are released in a comprehensive climate model simulation of the last glacial maximum (LGM), as well as a simulation of the modern climate. The two simulated climates result in qualitatively similar distributions of iceberg meltwater and hence debris, with the colder temperatures of the LGM having only a relatively small effect on meltwater spread. In both scenarios, meltwater flux falls off rapidly with zonal distance from the source, in contrast with the more uniform spread of IRD in sediment cores. To address this discrepancy, we propose a physical mechanism that could have prolonged the lifetime of icebergs during Heinrich events. The mechanism involves a surface layer of cold and fresh meltwater formed from, and retained around, large densely packed armadas of icebergs. This leads to wintertime sea ice formation even in relatively low latitudes. The sea ice in turn shields the icebergs from wave erosion, which is the main source of iceberg ablation. We find that sea ice could plausibly have formed around the icebergs during four months each winter. Allowing for four months of sea ice in the model results in a simulated IRD distribution which approximately agrees with the distribution of IRD in sediment cores. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109821
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: University of North Carolina Wilmington, United States; Scripps Institution of Oceanography, University of California San Diego, United States; Earth and Space Research, Corvallis, OR, United States
Recommended Citation:
Wagner T.J.W.,Dell R.W.,Eisenman I.,et al. Wave inhibition by sea ice enables trans-Atlantic ice rafting of debris during Heinrich events[J]. Earth and Planetary Science Letters,2018-01-01,495