气候变化领域集成服务门户(CCPortal): Isotopic exchange on the diurnal scale between near-surface snow and lower atmospheric water vapor at Kohnen station, East Antarctica

CCPortal

DOI	10.5194/tc-10-1647-2016
	Isotopic exchange on the diurnal scale between near-surface snow and lower atmospheric water vapor at Kohnen station, East Antarctica
	Ritter F.; Christian Steen-Larsen H.; Werner M.; Masson-Delmotte V.; Orsi A.; Behrens M.; Birnbaum G.; Freitag J.; Risi C.; Kipfstuhl S.
发表日期	2016
ISSN	19940416
卷号	10 期号:4
英文摘要	Quantifying the magnitude of post-depositional processes affecting the isotopic composition of surface snow is essential for a more accurate interpretation of ice core data. To achieve this, high temporal resolution measurements of both lower atmospheric water vapor and surface snow isotopic composition are required. This study presents continuous measurements of water vapor isotopes performed in East Antarctica (Kohnen station) from December 2013 to January 2014 using a laser spectrometer. Observations have been compared with the outputs of two atmospheric general circulation models (AGCMs) equipped with water vapor isotopes: ECHAM5-wiso and LMDZ5Aiso. During our monitoring period, the signals in the 2m air temperature T, humidity mixing ratio q and both water vapor isotopes δD and δ18O are dominated by the presence of diurnal cycles. Both AGCMs simulate similar diurnal cycles with a mean amplitude 30 to 70% lower than observed, possibly due to an incorrect simulation of the surface energy balance and the boundary layer dynamics. In parallel, snow surface samples were collected each hour over 35h, with a sampling depth of 2-5 mm. A diurnal cycle in the isotopic composition of the snow surface is observed in phase with the water vapor, reaching a peak-to-peak amplitude of 3‰ for δD over 24 h (compared to 36 ‰ for δD in the water vapor). A simple box model treated as a closed system has been developed to study the exchange of water molecules between an air and a snow reservoir. In the vapor, the box model simulations show too much isotopic depletion compared to the observations. Mixing with other sources (advection, free troposphere) has to be included in order to fit the observations. At the snow surface, the simulated isotopic values are close to the observations with a snow reservoir of ∼5 mm depth (range of the snow sample depth). Our analysis suggests that fractionation occurs during sublimation and that vapor-snow exchanges can no longer be considered insignificant for the isotopic composition of near-surface snow in polar regions.
学科领域	atmospheric general circulation model; diurnal variation; energy balance; fractionation; ice core; isotopic analysis; isotopic composition; oxygen isotope; polar region; snow cover; sublimation; surface energy; water exchange; water vapor; Antarctica; East Antarctica
语种	英语
scopus关键词	atmospheric general circulation model; diurnal variation; energy balance; fractionation; ice core; isotopic analysis; isotopic composition; oxygen isotope; polar region; snow cover; sublimation; surface energy; water exchange; water vapor; Antarctica; 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/119609
作者单位	Alfred-Wegener-Institut (AWI), Helmholtz Zentrum für Polar und Meeresforschung, Bremerhaven, Germany; Laboratoire des Sciences du Climat et de l'Environnement (LSCE), IPSL, CEA-CNRS-UVSQ, Saclay, Gif-sur-Yvette, France; Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark; Laboratoire de Méteórologie Dynamique (LMD), IPSL, CNRS-UPMC, Paris, France
推荐引用方式 GB/T 7714	Ritter F.,Christian Steen-Larsen H.,Werner M.,et al. Isotopic exchange on the diurnal scale between near-surface snow and lower atmospheric water vapor at Kohnen station, East Antarctica[J],2016,10(4).
APA	Ritter F..,Christian Steen-Larsen H..,Werner M..,Masson-Delmotte V..,Orsi A..,...&Kipfstuhl S..(2016).Isotopic exchange on the diurnal scale between near-surface snow and lower atmospheric water vapor at Kohnen station, East Antarctica.Cryosphere,10(4).
MLA	Ritter F.,et al."Isotopic exchange on the diurnal scale between near-surface snow and lower atmospheric water vapor at Kohnen station, East Antarctica".Cryosphere 10.4(2016).