Recent summer sea ice thickness surveys in Fram Strait and associated ice volume fluxes
Fram Strait is the main gateway for sea ice export out of the Arctic Ocean, and therefore observations there give insight into the composition and properties of Arctic sea ice in general and how it varies over time. A data set of ground-based and airborne electromagnetic ice thickness measurements c...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-03-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/10/523/2016/tc-10-523-2016.pdf |
| Summary: | Fram Strait is the main gateway for sea ice export out of the Arctic Ocean,
and therefore observations there give insight into the composition and properties
of Arctic sea ice in general and how it varies over time. A data set of
ground-based and airborne electromagnetic ice thickness measurements
collected during summer between 2001 and 2012 is presented here, including
long transects well into the southern part of the Transpolar Drift obtained
using fixed-wing aircrafts. The primary source of the surveyed sea ice
leaving Fram Strait is the Laptev Sea and its age has decreased from 3 to
2 years between 1990 and 2012. The thickness data consistently also show a
general thinning of sea ice for the last decade, with a decrease in modal
thickness of second year and multiyear ice, and a decrease in mean thickness
and fraction of ice thicker than 3 m. Local melting in the strait was
investigated in two surveys performed in the downstream direction, showing a
decrease in sea ice thickness of 0.19 m degree<sup>−1</sup> latitude south of
81° N. Further north variability in ice thickness is more related to
differences in age and deformation. The thickness observations were combined
with ice area export estimates to calculate summer volume fluxes of sea ice.
While satellite data show that monthly ice area export had positive trends
since 1980 (10.9 × 10<sup>3</sup> km<sup>2</sup> decade<sup>−1</sup>), the summer
(July and August) ice area export is low with high uncertainties. The average
volume export amounts to 16.78 km<sup>3</sup>. Naturally, the volume flux
estimates are limited to the period when airborne thickness surveys are
available. Nevertheless, we could show that the combination of satellite data
and airborne observations can be used to determine volume fluxes through Fram
Strait and as such, can be used to bridge the lack of satellite-based sea ice
thickness information in summer. |
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| ISSN: | 1994-0416 1994-0424 |