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Sea‐ice thickness from field measurements in the northwestern B arents S ea
Author(s) -
King Jennifer,
Spreen Gunnar,
Gerland Sebastian,
Haas Christian,
Hendricks Stefan,
Kaleschke Lars,
Wang Caixin
Publication year - 2017
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2016jc012199
Subject(s) - sea ice , arctic ice pack , sea ice thickness , antarctic sea ice , drift ice , geology , fast ice , sea ice concentration , cryosphere , oceanography , pancake ice , ice shelf , climatology
The Barents Sea is one of the fastest changing regions of the Arctic, and has experienced the strongest decline in winter‐time sea‐ice area in the Arctic, at − 23 ± 4 % decade −1 . Sea‐ice thickness in the Barents Sea is not well studied. We present two previously unpublished helicopter‐borne electromagnetic (HEM) ice thickness measurements from the northwestern Barents Sea acquired in March 2003 and 2014. The HEM data are compared to ice thickness calculated from ice draft measured by ULS deployed between 1994 and 1996. These data show that ice thickness varies greatly from year to year; influenced by the thermodynamic and dynamic processes that govern local formation vs long‐range advection. In a year with a large inflow of sea‐ice from the Arctic Basin, the Barents Sea ice cover is dominated by thick multiyear ice; as was the case in 2003 and 1995. In a year with an ice cover that was mainly grown in situ, the ice will be thin and mechanically unstable; as was the case in 2014. The HEM data allow us to explore the spatial and temporal variability in ice thickness. In 2003 the dominant ice class was more than 2 years old; and modal sea‐ice thickness varied regionally from 0.6 to 1.4 m, with the thinner ice being either first‐year ice, or multiyear ice which had come into contact with warm Atlantic water. In 2014 the ice cover was predominantly locally grown ice less than 1 month old (regional modes of 0.5–0.8 m). These two situations represent two extremes of a range of possible ice thickness distributions that can present very different conditions for shipping traffic; or have a different impact on heat transport from ocean to atmosphere.