气候变化领域集成服务门户(CCPortal): Mysteriously high I14C of the glacial atmosphere: Influence of 14C production and carbon cycle changes

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DOI	10.5194/cp-16-1159-2020
	Mysteriously high I14C of the glacial atmosphere: Influence of 14C production and carbon cycle changes
	Dinauer A.; Adolphi F.; Joos F.
发表日期	2020
ISSN	18149324
起始页码	1159
结束页码	1185
卷号	16 期号:4
英文摘要	Despite intense focus on the span classCombining double low lineinline-formulag1/4190/span drop in atmospheric span classCombining double low lineinline-formulaI14C/span during Heinrich Stadial 1 at span classCombining double low lineinline-formulag1/417.4/span-14.6 span classCombining double low lineinline-formulaka/span, the specific mechanisms responsible for the apparent span classCombining double low lineinline-formulaI14C/span excess in the glacial atmosphere have received considerably less attention. The computationally efficient Bern3D Earth system model of intermediate complexity, designed for long-term climate simulations, allows us to address a very fundamental but still elusive question concerning the atmospheric span classCombining double low lineinline-formulaI14C/span record: how can we explain the persistence of relatively high span classCombining double low lineinline-formulaI14C/span values during the millennia after the Laschamp event? Large uncertainties in the pre-Holocene span classCombining double low lineinline-formula14C/span production rate, as well as in the older portion of the span classCombining double low lineinline-formulaI14C/span record, complicate our qualitative and quantitative interpretation of the glacial span classCombining double low lineinline-formulaI14C/span elevation. Here we begin with sensitivity experiments that investigate the controls on atmospheric span classCombining double low lineinline-formulaI14C/span in idealized settings. We show that the interaction with the ocean sediments may be much more important to the simulation of span classCombining double low lineinline-formulaI14C/span than had been previously thought. In order to provide a bounded estimate of glacial span classCombining double low lineinline-formulaI14C/span change, the Bern3D model was integrated with five available estimates of the span classCombining double low lineinline-formula14C/span production rate as well as reconstructed and hypothetical paleoclimate forcing. Model results demonstrate that none of the available reconstructions of past changes in span classCombining double low lineinline-formula14C/span production can reproduce the elevated span classCombining double low lineinline-formulaI14C/span levels during the last glacial. In order to increase atmospheric span classCombining double low lineinline-formulaI14C/span to glacial levels, a drastic reduction of air-sea exchange efficiency in the polar regions must be assumed, though discrepancies remain for the portion of the record younger than span classCombining double low lineinline-formulag1/433/span span classCombining double low lineinline-formulaka/span. We end with an illustration of how the span classCombining double low lineinline-formula14C/span production rate would have had to evolve to be consistent with the span classCombining double low lineinline-formulaI14C/span record by combining an atmospheric radiocarbon budget with the Bern3D model. The overall conclusion is that the remaining discrepancies with respect to glacial span classCombining double low lineinline-formulaI14C/span may be linked to an underestimation of span classCombining double low lineinline-formula14C/span production and/or a biased-high reconstruction of span classCombining double low lineinline-formulaI14C/span over the time period of interest. Alternatively, we appear to still be missing an important carbon cycle process for atmospheric span classCombining double low lineinline-formulaI14C/span. © 2020, Mary Ann Liebert, Inc., publishers 2020.
语种	英语
scopus关键词	carbon cycle; glacial environment; paleoclimate; paleoenvironment; radiocarbon dating
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146699
作者单位	Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Sidlerstrasse 5, Bern, 3012, Switzerland; Quaternary Sciences, Department of Geology, Lund University, Sölvegatan 12, Lund, 22362, Sweden
推荐引用方式 GB/T 7714	Dinauer A.,Adolphi F.,Joos F.. Mysteriously high I14C of the glacial atmosphere: Influence of 14C production and carbon cycle changes[J],2020,16(4).
APA	Dinauer A.,Adolphi F.,&Joos F..(2020).Mysteriously high I14C of the glacial atmosphere: Influence of 14C production and carbon cycle changes.Climate of the Past,16(4).
MLA	Dinauer A.,et al."Mysteriously high I14C of the glacial atmosphere: Influence of 14C production and carbon cycle changes".Climate of the Past 16.4(2020).