DOI: 10.5194/cp-8-1239-2012
Scopus记录号: 2-s2.0-84864612439
论文题名: On the gas-ice depth difference (Δdepth) along the EPICA Dome C ice core
作者: Parrenin F. ; Barker S. ; Blunier T. ; Chappellaz J. ; Jouzel J. ; Landais A. ; Masson-Delmotte V. ; Schwander J. ; Veres D.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2012
卷: 8, 期: 4 起始页码: 1239
结束页码: 1255
语种: 英语
Scopus关键词: accumulation rate
; climate variation
; convection
; ice core
; ice flow
; ice thickness
; isotopic analysis
; Last Glacial
; paleoclimate
; proxy climate record
; Antarctica
; Dome Concordia
; East Antarctica
英文摘要: We compare a variety of methods for estimating the gas/ice depth offset (Δdepth) at EPICA Dome C (EDC, East Antarctica). (1) Purely based on modelling efforts, Δdepth can be estimated combining a firn densification with an ice flow model. (2) The diffusive column height can be estimated from δ15N and converted to Δdepth using an ice flow model and assumptions about past average firn density and thickness of the convective zone. (3) Ice and gas synchronisation of the EDC ice core to the GRIP, EDML and TALDICE ice cores shifts the ice/gas offset problem into higher accumulation ice cores where it can be more accurately evaluated. (4) Finally, the bipolar seesaw hypothesis allows us to synchronise the ice isotopic record with the gas CH4 record, the later being taken as a proxy of Greenland temperature. The general agreement of method 4 with methods 2 and 3 confirms that the bipolar seesaw antiphase happened during the last 140 kyr. Applying method 4 to the deeper section of the EDC core confirms that the ice flow is complex and can help to improve our reconstruction of the thinning function and thus, of the EDC age scale. We confirm that method 1 overestimates the glacial Δdepth at EDC and we suggest that it is due to an overestimation of the glacial lock-in depth (LID) by the firn densification model. In contrast, we find that method 1 very likely underestimates Δdepth during Termination II, due either to an underestimated thinning function or to an underestimated LID. Finally, method 2 gives estimates within a few metres of methods 3 and 4 during the last deglacial warming, suggesting that the convective zone at Dome C cannot have been very large at this time, if it existed at all. © 2012 Author(s). CC Attribution 3.0 License. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49566
Appears in Collections: 气候变化与战略
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Recommended Citation:
Parrenin F.,Barker S.,Blunier T.,et al. On the gas-ice depth difference (Δdepth) along the EPICA Dome C ice core[J]. Climate of the Past,2012-01-01,8(4)