dc.contributor |
Háskóli Íslands |
dc.contributor |
University of Iceland |
dc.contributor |
Landbúnaðarháskóli Íslands |
dc.contributor |
Agricultural University of Iceland |
dc.contributor.author |
Wittmann, Monika |
dc.contributor.author |
Groot Zwaaftink, Christine |
dc.contributor.author |
Steffensen Schmidt, Louise |
dc.contributor.author |
Guðmundsson, Sverrir |
dc.contributor.author |
Pálsson, Finnur |
dc.contributor.author |
Arnalds, Olafur |
dc.contributor.author |
Björnsson, Helgi |
dc.contributor.author |
Thorsteinsson, Throstur |
dc.contributor.author |
Stohl, Andreas |
dc.date.accessioned |
2017-05-22T16:10:35Z |
dc.date.available |
2017-05-22T16:10:35Z |
dc.date.issued |
2017-03-23 |
dc.identifier.citation |
Wittmann, M., Groot Zwaaftink, C. D., Steffensen Schmidt, L., Guðmundsson, S., Pálsson, F., Arnalds, O., Björnsson, H., Thorsteinsson, T., and Stohl, A.: Impact of dust deposition on the albedo of Vatnajökull ice cap, Iceland, The Cryosphere, 11, 741-754, doi:10.5194/tc-11-741-2017, 2017. |
dc.identifier.issn |
1994-0416 |
dc.identifier.issn |
1994-0424 (eISSN) |
dc.identifier.uri |
https://hdl.handle.net/20.500.11815/274 |
dc.description.abstract |
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 ( ∼ 1210 m a.s.l.), the dispersion model produced 10 major dust deposition events and a total annual deposition of 20.5 g m−2. At the station located higher on the glacier ( ∼ 1525 m a.s.l.), the model produced nine dust events, with one single event causing ∼ 5 g m−2 of dust deposition and a total deposition of ∼ 10 g m−2 yr−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 1.1 m w.e. (water equivalent) of snowmelt (or 42 % of the 2.8 m w.e. total melt) compared to a hypothetical clean glacier surface at the lower station, and 0.6 m w.e. more melt (or 38 % of the 1.6 m w.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. |
dc.description.sponsorship |
The study described in this manuscript was supported by NordForsk as part of the two Nordic Centres of Excellence Cryosphere-Atmosphere Interactions in a Changing Arctic climate (CRAICC), and eScience Tools for Investigating Climate Change (eSTICC). Part of this work was supported by the Centre of Excellence in Atmospheric Science funded by the Finnish Academy of Sciences Excellence (project no. 272041), by the Finnish Academy of Sciences project A4 (contract 254195). Data from in situ mass balance surveys and on glacier automatic weather stations are from joint projects of the National Power Company and the Glaciology group of the Institute of Earth Science, University of Iceland. C. Groot Zwaaftink was also funded by the Swiss National Science Foundation SNF (155294), and Louise Steffensen-Schmidt, Finnur Palsson and Sverrir Gudmunds-son by the Icelandic Research Fund (project SAMAR) and the National Power Company of Iceland. Olafur Arnalds was in part funded by Icelandic Research Fund (grant no. 152248-051) |
dc.format.extent |
741-754 |
dc.language.iso |
en |
dc.publisher |
Copernicus GmbH |
dc.relation.ispartofseries |
The Cryosphere;11(2) |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.subject |
Vatnajökull |
dc.subject |
Bráðnun (jöklafræði) |
dc.subject |
Svifryk |
dc.subject |
Jöklarannsóknir |
dc.title |
Impact of dust deposition on the albedo of Vatnajökull ice cap, Iceland |
dc.type |
info:eu-repo/semantics/article |
dcterms.license |
This work is distributed under the Creative Commons Attribution 3.0 License. |
dc.description.version |
Peer Reviewed |
dc.identifier.journal |
The Cryosphere |
dc.identifier.doi |
10.5194/tc-11-741-2017 |
dc.relation.url |
http://www.the-cryosphere.net/11/741/2017/ |
dc.contributor.department |
Jarðvísindastofnun (HÍ) |
dc.contributor.department |
Institute of Earth Sciences (UI) |
dc.contributor.department |
Auðlinda- og umhverfisdeild (LBHÍ) |
dc.contributor.department |
Faculty of Natural Resources and Environmental Sciences (AUI) |
dc.contributor.school |
Verkfræði- og náttúruvísindasvið (HÍ) |
dc.contributor.school |
School of Engineering and Natural Sciences (UI) |