DOI: 10.1016/j.quascirev.2016.01.026
Scopus记录号: 2-s2.0-84960903666
论文题名: Internal ice - Sheet variability as source for the multi-century and millennial-scale iceberg events during the Holocene? A model study
作者: Bügelmayer-Blaschek M. ; Roche D.M. ; Renssen H. ; Andrews J.T.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2016
卷: 138 起始页码: 119
结束页码: 130
语种: 英语
英文关键词: Bond events
; Climate modeling
; Greenland ice sheet
; Holocene
; Icebergs
Scopus关键词: Climate change
; Glaciers
; Ice
; Sea ice
; Spectrum analysis
; Volcanoes
; Different mechanisms
; Greenland Ice Sheet
; Holocenes
; Icebergs
; Initial atmospheric conditions
; Internal climate variability
; Proxy reconstruction
; Total solar irradiance
; Climate models
; climate conditions
; climate modeling
; climate variation
; Holocene
; ice sheet
; ice-ocean interaction
; ice-rafted debris
; iceberg
; meltwater
; proxy climate record
; spectral analysis
; Arctic
; Greenland
; Greenland Ice Sheet
英文摘要: The climate of the Holocene, the current interglacial covering the past 11,700 years, has been relatively stable compared to previous periods. Nevertheless, repeating occurrence of rapid natural climate changes that challenged human society are seen in proxy reconstructions. Ocean sediment cores for example display prominent peaks of enhanced ice rafted debris (IRD) during the Holocene with a multi-decadal to millennial scale periodicity. Different mechanisms were proposed that caused these enhanced IRD events, for example variations in the incoming total solar irradiance (TSI), volcanic eruptions and the combination of internal climate variability and external forcings. We investigate the probable mechanisms causing the occurrence of IRD-events over the past 6000 years using a fully coupled climate - ice-sheet - iceberg model (iLOVECLIM). We performed 19 experiments that differ in the applied forcings (TSI, volcanic) and the initial atmospheric conditions. To explore internal ice sheet variability one further experiment was done with fixed climate conditions. All the model runs displayed prominent peaks of enhanced iceberg melt flux (IMF), independent of the chosen experimental set-up. The spectral analysis of the experiments with the ice-sheet - climate model coupled displays significant peaks at 2000, 1000 years in all the experiments and at 500 years in most runs. The experiment with fixed climate conditions displays one significant peak of about 1500 years related to internal ice sheet variability. This frequency is modulated to 2000 and 1000 years in all the experiments with a coupled climate - ice sheet due to interactions between the climate components. We further investigate the impact of minimum TSI events on the timing and occurrence of enhanced IMF. In the experimental set-up that was forced with idealized sinusoidal TSI variations (±4 Wm-2), we find a significant occurrence of an increased iceberg melt flux about 60 years after the minimum TSI value. Yet, we also see a significant time lag of 80 years between reconstructed TSI minima and the simulated enhanced iceberg melt flux in some of the experiments without TSI forcing. The fact that also model runs that are not forced with TSI variations display an 80 year time lag indicates that the relationship between TSI and IMF is due to internal dynamics of the coupled system. From our experiments we conclude that internal ice sheet variability seems to be the source of the multi-century and millennial-scale iceberg events during the Holocene. © 2016 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59633
Appears in Collections: 过去全球变化的重建
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作者单位: Earth and Climate Cluster, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands; Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France; INSTAAR and Department of Geological Sciences, University of Colorado, Boulder, CO, United States; Department of Geological Sciences, University of Colorado, Boulder, CO, United States
Recommended Citation:
Bügelmayer-Blaschek M.,Roche D.M.,Renssen H.,et al. Internal ice - Sheet variability as source for the multi-century and millennial-scale iceberg events during the Holocene? A model study[J]. Quaternary Science Reviews,2016-01-01,138