Recirculation in the Fram Strait and transports of water in and north of the Fram Strait derived from CTD data 1Finnish Meteorological Institute, Helsinki, Finland
14 May 2013
2University of Helsinki, Helsinki, Finland
3Laboratoire d'océanographie et du climat: expérimentations et approches numériques (LOCEAN), Unité mixte CNRS/UPMC/IRD/MNHN, Université Pierre et Marie Curie, Paris, France
4Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
Received: 13 September 2012 – Published in Ocean Sci. Discuss.: 10 October 2012 Abstract. The volume, heat and freshwater transports in the Fram Strait are estimated
from geostrophic computations based on summer hydrographic data from 1984,
1997, 2002 and 2004. In these years, in addition to the usually sampled
section along 79° N, a section between Greenland and Svalbard was
sampled further north. Quasi-closed boxes bounded by the two sections and
Greenland and Svalbard can then be formed. Applying conservation constraints
on these boxes provides barotropic reference velocities. The net volume flux
is southward and varies between 2 and 4 Sv. The recirculation of Atlantic
water is about 2 Sv. Heat is lost to the atmosphere and the heat loss from
the area between the sections averaged over the four years is about 10 TW.
The net heat (temperature) transport is 20 TW northward into the Arctic
Ocean, with large interannual differences. The mean net freshwater added
between the sections is 40 mSv and the mean freshwater transport southward
across 79° N is less than 60 mSv, indicating that most of the liquid
freshwater leaving the Arctic Ocean through Fram Strait in summer is derived
from sea ice melt in the northern vicinity of the strait.
In 1997, 2001 and 2003 meridional sections along 0° longitude were
sampled and in 2003 two smaller boxes can be formed, and the recirculation of
Atlantic water in the strait is estimated by geostrophic computations and
continuity constraints. The recirculation is weaker close to 80° N
than close to 78° N, indicating that the recirculation is mainly
confined to the south of 80° N. This is supported by the observations in
1997 and 2001, when only the northern part of the meridional section, from
79° N to 80° N, can be computed with the constraints applied.
The recirculation is found strongest close to 79° N.
Revised: 28 March 2013 – Accepted: 16 April 2013 – Published: 14 May 2013
Citation: Marnela, M., Rudels, B., Houssais, M.-N., Beszczynska-Möller, A., and Eriksson, P. B.: Recirculation in the Fram Strait and transports of water in and north of the Fram Strait derived from CTD data, Ocean Sci., 9, 499-519, doi:10.5194/os-9-499-2013, 2013.