The influence of regional circulation patterns on wet and dry mineral dust and sea salt deposition over Greenland |
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| Authors: | M A Hutterli T Crueger H Fischer K K Andersen C C Raible T F Stocker M L Siggaard-Andersen J R McConnell R C Bales J F Burkhart |
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| Institution: | (1) Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland;(2) Physical Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK;(3) Max-Planck-Institute for Meteorology, Hamburg, Bundesstrasse 53, 20146 Hamburg, Germany;(4) Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Columbusstrasse, 27568 Bremerhaven, Germany;(5) Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, Denmark;(6) Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512, USA;(7) University of California, Merced, 4225 N. Hospital Road, Atwater, CA 95301, USA |
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| Abstract: | Annually resolved ice core records from different regions over the Greenland ice sheet (GrIS) are used to investigate the
spatial and temporal variability of calcium (Ca2+, mainly from mineral dust) and sodium (Na+, mainly from sea salt) deposition. Cores of high common inter-annual variability are grouped with an EOF analysis, resulting
in regionally representative Ca2+ and Na+ records for northeastern and central Greenland. Utilizing a regression and validation method with ERA-40 reanalysis data,
these common records are associated with distinct regional atmospheric circulation patterns over the North American Arctic,
Greenland, and Central to Northern Europe. These patterns are interpreted in terms of transport and deposition of the impurities.
In the northeastern part of the GrIS sea salt records reflect the intrusion of marine air masses from southeasterly flow.
A large fraction of the Ca2+ variability in this region is connected to a circulation pattern suggesting transport from the west and dry deposition. This
pattern is consistent with the current understanding of a predominantly Asian source of the dust deposited over the GrIS.
However, our results also indicate that a significant fraction of the inter-annual dust variability in NE and Central Greenland
is determined by the frequency and intensity of wet deposition during the season of high atmospheric dust loading, rather
than representing the variability of the Asian dust source and/or long-range transport to Greenland. The variances in the
regional proxy records explained by the streamfunction patterns are high enough to permit reconstructions of the corresponding
regional deposition regimes and the associated circulation patterns. |
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