气候变化领域集成服务门户(CCPortal): A 60-year ice-core record of regional climate from Adélie Land, coastal Antarctica

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DOI	10.5194/tc-11-343-2017
	A 60-year ice-core record of regional climate from Adélie Land, coastal Antarctica
	Goursaud S.; Masson-Delmotte V.; Favier V.; Preunkert S.; Fily M.; Gallée H.; Jourdain B.; Legrand M.; Magand O.; Minster B.; Werner M.
发表日期	2017
ISSN	19940416
卷号	11 期号:1
英文摘要	A 22.4 m-long shallow firn core was extracted during the 2006/2007 field season from coastal Adélie Land. Annual layer counting based on subannual analyses of δ18O and major chemical components was combined with 5 reference years associated with nuclear tests and non-retreat of summer sea ice to build the initial ice-core chronology (1946-2006), stressing uncertain counting for 8 years. We focus here on the resulting δ18O and accumulation records. With an average value of 21.8±6.9 cm w.e. yr-1, local accumulation shows multi-decadal variations peaking in the 1980s, but no long-term trend. Similar results are obtained for δ18O, also characterised by a remarkably low and variable amplitude of the seasonal cycle. The ice-core records are compared with regional records of temperature, stake area accumulation measurements and variations in sea-ice extent, and outputs from two models nudged to ERA (European Reanalysis) atmospheric reanalyses: the high-resolution atmospheric general circulation model (AGCM), including stable water isotopes ECHAM5-wiso (European Centre Hamburg model), and the regional atmospheric model Modèle Atmosphérique Régional (AR). A significant linear correlation is identified between decadal variations in δ18O and regional temperature. No significant relationship appears with regional sea-ice extent. A weak and significant correlation appears with Dumont d'Urville wind speed, increasing after 1979. The model-data comparison highlights the inadequacy of ECHAM5-wiso simulations prior to 1979, possibly due to the lack of data assimilation to constrain atmospheric reanalyses. Systematic biases are identified in the ECHAM5-wiso simulation, such as an overestimation of the mean accumulation rate and its interannual variability, a strong cold bias and an underestimation of the mean δ18O value and its interannual variability. As a result, relationships between simulated δ18O and temperature are weaker than observed. Such systematic precipitation and temperature biases are not displayed by MAR, suggesting that the model resolution plays a key role along the Antarctic ice sheet coastal topography. Interannual variations in ECHAM5-wiso temperature and precipitation accurately capture signals from meteorological data and stake observations and are used to refine the initial ice-core chronology within 2 years. After this adjustment, remarkable positive (negative) δ18O anomalies are identified in the ice-core record and the ECHAM5-wiso simulation in 1986 and 2002 (1998-1999), respectively. Despite uncertainties associated with post-deposition processes and signal-to-noise issues, in one single coastal ice-core record, we conclude that the S1C1 core can correctly capture major annual anomalies in δ18O as well as multi-decadal variations. These findings highlight the importance of improving the network of coastal high-resolution ice-core records, and stress the skills and limitations of atmospheric models for accumulation and δ18O in coastal Antarctic areas. This is particularly important for the overall East Antarctic ice sheet mass balance. © Author(s) 2017.
学科领域	atmospheric general circulation model; data assimilation; ice core; ice sheet; mass balance; oxygen isotope; regional climate; sea ice; stable isotope; Adelie Coast; Antarctica; Dumont d'Urville; East Antarctica
语种	英语
scopus关键词	atmospheric general circulation model; data assimilation; ice core; ice sheet; mass balance; oxygen isotope; regional climate; sea ice; stable isotope; Adelie Coast; Antarctica; Dumont d'Urville; East Antarctica
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119447
作者单位	LSCE, UMR CEA-CNRS-UVSQ 8212-IPSL, Université Paris Saclay, Gif-sur-Yvette, France; Univ. Grenoble Alpes, CNRS, IRD, IGE, Grenoble, 38000, France; CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), Grenoble, 38041, France; Alfred Wegener Institute for Polar and Marine Research (AWI), Bremerhaven, Germany
推荐引用方式 GB/T 7714	Goursaud S.,Masson-Delmotte V.,Favier V.,et al. A 60-year ice-core record of regional climate from Adélie Land, coastal Antarctica[J],2017,11(1).
APA	Goursaud S..,Masson-Delmotte V..,Favier V..,Preunkert S..,Fily M..,...&Werner M..(2017).A 60-year ice-core record of regional climate from Adélie Land, coastal Antarctica.Cryosphere,11(1).
MLA	Goursaud S.,et al."A 60-year ice-core record of regional climate from Adélie Land, coastal Antarctica".Cryosphere 11.1(2017).