Characterizing fjord oceanography near tidewater glaciers Kronebreen and Kongsvegen, in Kongsfjorden, Svalbard
Date
2012-07-03
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Abstract
In recent years, warmer Atlantic-origin waters have intruded into Svalbard's west-
coast fjords. To predict the e ects of the TAW (transformed Atlantic water) intrusion
on the ice margin of tidewater glaciers, a detailed understanding of fjord circulation
is important. While the general fjord circulation of Kongsfjorden, Svalbard, is well-
understood, water masses closest to the ice margin { and directly responsible for sub-
marine glacial melt { are more di cult to study. To characterize the water masses and
interpret fjord circulation at the calving-fronts of glaciers Kronebreen and Kongsvegen,
Svalbard, oceanographic eldwork was conducted along ve primary transects, with the
view to account for tidal in
uences as well. CTD (conductivity, temperature, depth)
devices with attached OBS (relative turbidity) sensors were used to collect data that
range from 200 m to 1.7 km from the ice face, between 22 Jul and 6 Aug 2011. Current
velocities were also estimated using drogues constructed while in Svalbard. The data
show signi cantly variability in the water column strati cation between just days. In
addition to the tidal cycle, winds and other factors also appear to play a major role
in glacial discharge streams and circulation. A comparison with data collected in the
same region in Jul 2005 (by Trusel et al. 2010) show the 2011 Intermediate Water (IW)
at depth to be warmer than the 0 local water (LC) that was observed at comparable
depths in 2005. These two layers lie above the TAW and may be warmer as a result of
convection with increased TAW waters. Increased intrusion of Atlantic-origin waters
after 2005 are likely to have warmed the waters in the inner fjord of Kongsfjorden,
indicating that the ice margin of tidewater glaciers in Kongsfjorden are susceptible to
heat fuxes from North Atlantic water intrusions.
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Keywords
oceanography, Kongsfjord, fjord