Tidally induced lateral dispersion of the Storfjorden overflow plume 1School of Marine Science and Engineering, University of Plymouth, Plymouth, PL4 8AA, UK
28 Oct 2013
2Shirshov Institute of Oceanology, 36 Nahimovski prospect, Moscow, 117997, Russia
3National Oceanography Centre, Joseph Proudman Building, 6 Brownlow Street, Liverpool, L3 5DA, UK
4National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK
Received: 14 March 2013 – Published in Ocean Sci. Discuss.: 08 April 2013 Abstract. We investigate the flow of brine-enriched shelf water from Storfjorden
(Svalbard) into Fram Strait and onto the western Svalbard Shelf using
a regional set-up of NEMO-SHELF, a 3-D numerical ocean circulation
model. The model is set up with realistic bathymetry, atmospheric
forcing, open boundary conditions and tides.
The model has 3 km horizontal resolution and 50 vertical levels in
the sh-coordinate system which is specially designed to resolve
bottom boundary layer processes. In a series of modelling experiments we
focus on the influence of tides on the propagation of the dense water plume
results from tidal and non-tidal model runs.
Comparisons of non-tidal to tidal simulations reveal a hotspot of
tidally induced horizontal diffusion leading to the lateral dispersion
of the plume at the southernmost headland of Spitsbergen which is in
close proximity to the plume path.
As a result the lighter fractions in the diluted upper layer of the
plume are drawn into the shallow coastal current that carries
Storfjorden water onto the western Svalbard Shelf, while the dense
bottom layer continues to sink down the slope.
This bifurcation of the plume into a diluted shelf branch and a dense
downslope branch is enhanced by tidally induced shear dispersion at
Tidal effects at the headland are shown to cause a net reduction in the downslope flux of Storfjorden water into the deep Fram Strait.
This finding contrasts previous results from observations of a dense plume on a different shelf without abrupt topography.
Revised: 17 July 2013 – Accepted: 23 September 2013 – Published: 28 October 2013
Citation: Wobus, F., Shapiro, G. I., Huthnance, J. M., Maqueda, M. A. M., and Aksenov, Y.: Tidally induced lateral dispersion of the Storfjorden overflow plume, Ocean Sci., 9, 885-899, doi:10.5194/os-9-885-2013, 2013.