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| Titel |
The impact of heterogeneous surface temperatures on the 2-m air temperature over the Arctic Ocean under clear skies in spring |
| VerfasserIn |
A. Tetzlaff, L. Kaleschke, C. Lüpkes, F. Ament, T. Vihma |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 7, no. 1 ; Nr. 7, no. 1 (2013-01-30), S.153-166 |
| Datensatznummer |
250017409
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| Publikation (Nr.) |
 copernicus.org/tc-7-153-2013.pdf |
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| Zusammenfassung |
| The influence of spatial surface temperature changes over the Arctic Ocean on
the 2-m air temperature variability is estimated using backward trajectories
based on ERA-Interim and JRA25 wind fields. They are initiated at Alert,
Barrow and at the Tara drifting station. Three different methods are used.
The first one compares mean ice surface temperatures along the trajectories
to the observed 2-m air temperatures at the stations. The second one
correlates the observed temperatures to air temperatures obtained using a
simple Lagrangian box model that only includes the effect of sensible heat
fluxes. For the third method, mean sensible heat fluxes from the model are
correlated with the difference of the air temperatures at the model starting
point and the observed temperatures at the stations. The calculations are
based on MODIS ice surface temperatures and four different sets of ice
concentration derived from SSM/I (Special Sensor Microwave Imager) and AMSR-E
(Advanced Microwave Scanning Radiometer for EOS) data. Under nearly
cloud-free conditions, up to 90% of the 2-m air temperature variance can
be explained for Alert, and 70% for Barrow, using these methods. The
differences are attributed to the different ice conditions, which are
characterized by high ice concentration around Alert and lower ice
concentration near Barrow. These results are robust for the different sets of
reanalyses and ice concentration data. Trajectories based on 10-m wind fields
from both reanalyses show large spatial differences in the Central Arctic,
leading to differences in the correlations between modeled and observed 2-m
air temperatures. They are most pronounced at Tara, where explained variances
amount to 70% using JRA and 80% using ERA. The results also suggest
that near-surface temperatures at a given site are influenced by the
variability of surface temperatures in a domain of about 200 km radius
around the site. |
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