气候变化领域集成服务门户(CCPortal): Constraining uncertainties in CMIP5 projections of September Arctic sea ice extent with observations

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DOI	10.1175/JCLI-D-19-0075.1
	Constraining uncertainties in CMIP5 projections of September Arctic sea ice extent with observations
	Senftleben D.; Lauer A.; Karpechko A.
发表日期	2020
ISSN	0894-8755
起始页码	1487
结束页码	1503
卷号	33 期号:4
英文摘要	In agreement with observations, Earth system models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5) simulate a decline in September Arctic sea ice extent (SIE) over the past decades. However, the spread in their twenty-first-century SIE projections is large and the timing of the first ice-free Arctic summer ranges from 2020 to beyond 2100. The uncertainties arise from three sources (internal variability, model uncertainty, and scenario uncertainty), which are quantified in this study for projections of SIE. The goal is to narrow uncertainties by applying multiple diagnostic ensemble regression (MDER). MDER links future projections of sea ice extent to processes relevant to its simulation under present-day conditions using data covering the past 40 years. With this method, we can reduce model uncertainty in projections of SIE for the period 2020–44 by 30%–50% (0.8–1.3 million km2). Compared to the unweighted multimodel mean, the MDER-weighted mean projects an about 20% smaller SIE and an earlier near-disappearance of Arctic sea ice by more than a decade for a high–greenhouse gas scenario. We also show that two different methods estimating internal variability in SIE differ by 1 million km2. Regardless, the total uncertainties in the SIE projections remain large (up to 3.5 million km2, with irreducible internal variability contributing 30%) so that a precise time estimate of an ice-free Arctic proves impossible. We conclude that unweighted CMIP5 multimodel-mean projections of Arctic SIE are too optimistic and mitigation strategies to reduce Arctic warming need to be intensified. © 2020 American Meteorological Society.
英文关键词	Climate models; Greenhouse gases; Sea ice; Arctic warming; Coupled Model Intercomparison Project; Earth system model; Future projections; Internal variability; Mitigation strategy; Model uncertainties; Total uncertainties; Uncertainty analysis; climate modeling; CMIP; forecasting method; global warming; greenhouse gas; regression analysis; sea ice; uncertainty analysis; Arctic Ocean
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/171442
作者单位	Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany; Finnish Meteorological Institute, Helsinki, Finland
推荐引用方式 GB/T 7714	Senftleben D.,Lauer A.,Karpechko A.. Constraining uncertainties in CMIP5 projections of September Arctic sea ice extent with observations[J],2020,33(4).
APA	Senftleben D.,Lauer A.,&Karpechko A..(2020).Constraining uncertainties in CMIP5 projections of September Arctic sea ice extent with observations.Journal of Climate,33(4).
MLA	Senftleben D.,et al."Constraining uncertainties in CMIP5 projections of September Arctic sea ice extent with observations".Journal of Climate 33.4(2020).