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| Titel |
Thin-ice dynamics and ice production in the Storfjorden polynya for winter seasons 2002/2003–2013/2014 using MODIS thermal infrared imagery |
| VerfasserIn |
A. Preußer, S. Willmes, G. Heinemann, S. Paul |
| 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 ; 9, no. 3 ; Nr. 9, no. 3 (2015-05-21), S.1063-1073 |
| Datensatznummer |
250116801
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| Publikation (Nr.) |
 copernicus.org/tc-9-1063-2015.pdf |
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| Zusammenfassung |
| Spatial and temporal characteristics of the Storfjorden polynya, which
forms regularly in the proximity of the islands Spitsbergen,
Barentsøya and Edgeøya in the Svalbard archipelago under the influence of
strong northeasterly winds, have been investigated for the period of
2002/2003 to 2013/2014 using thermal infrared satellite imagery. Thin-ice
thicknesses were calculated from MODIS ice-surface temperatures
combined with ECMWF ERA-Interim atmospheric reanalysis data in an
energy-balance model.
Associated quantities like polynya area and total ice production were
derived and compared to previous remote sensing and modeling
studies. A basic coverage-correction scheme was applied to account for
cloud gaps in the daily composites. On average, both polynya area and ice production are thereby increased by about 30%.
The sea ice in the Storfjorden area experiences a late fall freeze-up in several years over the 12-winter period, which becomes most apparent through an increasing frequency of large thin-ice areas
until the end of December. In the course of an average winter season, ice thicknesses below 10 cm are dominating within the Storfjorden basin.
During the regarded period, the mean polynya area is 4555.7 ± 1542.9 km2.
Maximum daily ice production rates can reach as high as 26 cm d−1, while the average ice
production is estimated at 28.3 ± 8.5 km3
per winter and therefore lower than in previous studies. Despite this
comparatively short record of 12 winter seasons, a significant
positive trend of 20.2 km3 per decade could be detected, which originates primarily from a delayed freeze-up in November and December in recent winter seasons.
This contrasts earlier reports of a slightly negative trend in accumulated
ice production prior to 2002. Although featuring more pronounced interannual variations between 2004/2005 and 2011/2012, our estimates underline the
importance of this relatively small coastal polynya system considering
its contribution to the cold halocline layer through salt release
during ice-formation processes. In addition, calculated quasi-daily thin-ice thickness charts represent a valuable data set for atmosphere and ocean modeling applications. |
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