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DOI	10.5194/tc-11-741-2017
	Impact of dust deposition on the albedo of Vatnajökull ice cap, Iceland
	Wittmann M.; Zwaaftink C.D.G.; Schmidt L.S.; Gumundsson S.; Pálsson F.; Arnalds O.; Björnsson H.; Thorsteinsson T.; Stohl A.
发表日期	2017
ISSN	19940416
卷号	11 期号:2
英文摘要	Deposition of small amounts of airborne dust on glaciers causes positive radiative forcing and enhanced melting due to the reduction of surface albedo. To study the effects of dust deposition on the mass balance of Brúarjökull, an outlet glacier of the largest ice cap in Iceland, Vatnajökull, a study of dust deposition events in the year 2012 was carried out. The dust-mobilisation module FLEXDUST was used to calculate spatio-temporally resolved dust emissions from Iceland and the dispersion model FLEXPART was used to simulate atmospheric dust dispersion and deposition. We used albedo measurements at two automatic weather stations on Brúarjökull to evaluate the dust impacts. Both stations are situated in the accumulation area of the glacier, but the lower station is close to the equilibrium line. For this site (∼ 1210ma.s.l.), the dispersion model produced 10 major dust deposition events and a total annual deposition of 20.5gm-2. At the station located higher on the glacier (∼ 1525ma.s.l.), the model produced nine dust events, with one single event causing ∼ 5gm-2 of dust deposition and a total deposition of ∼ 10gm-2yr-1. The main dust source was found to be the Dyngjusandur floodplain north of Vatnajökull; northerly winds prevailed 80% of the time at the lower station when dust events occurred. In all of the simulated dust events, a corresponding albedo drop was observed at the weather stations. The influence of the dust on the albedo was estimated using the regional climate model HIRHAM5 to simulate the albedo of a clean glacier surface without dust. By comparing the measured albedo to the modelled albedo, we determine the influence of dust events on the snow albedo and the surface energy balance. We estimate that the dust deposition caused an additional 1.1mw.e. (water equivalent) of snowmelt (or 42% of the 2.8mw.e. total melt) compared to a hypothetical clean glacier surface at the lower station, and 0.6mw.e. more melt (or 38% of the 1.6mw.e. melt in total) at the station located further upglacier. Our findings show that dust has a strong influence on the mass balance of glaciers in Iceland. © 2017 Author(s).
学科领域	albedo; atmospheric deposition; climate modeling; dust; energy balance; ice cap; radiative forcing; regional climate; snowmelt; surface energy; Iceland; Vatnajokull
语种	英语
scopus关键词	albedo; atmospheric deposition; climate modeling; dust; energy balance; ice cap; radiative forcing; regional climate; snowmelt; surface energy; Iceland; Vatnajokull
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/119421
作者单位	Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland; NILU-Norwegian Institute for Air Research, Kjeller, Norway; Keilir, Institute of Technology, Reykjanesbær, Iceland; Agricultural University of Iceland, Hvanneyri, Iceland
推荐引用方式 GB/T 7714	Wittmann M.,Zwaaftink C.D.G.,Schmidt L.S.,et al. Impact of dust deposition on the albedo of Vatnajökull ice cap, Iceland[J],2017,11(2).
APA	Wittmann M..,Zwaaftink C.D.G..,Schmidt L.S..,Gumundsson S..,Pálsson F..,...&Stohl A..(2017).Impact of dust deposition on the albedo of Vatnajökull ice cap, Iceland.Cryosphere,11(2).
MLA	Wittmann M.,et al."Impact of dust deposition on the albedo of Vatnajökull ice cap, Iceland".Cryosphere 11.2(2017).