FlexSemFlexSemAarhus University department of Ecoscience

Disko Bay, West Greeland

The Disko Bay is the largest bay on the west coast of Greenland. Connected to the Baffin Bay towards the west by a trench and a 300 m deep sill it has an average depth of 400 m and features a complex bathymetry of sills and trenches [12]. It has several long narrow sub fjords, among these the Ilulissat ice fjord with the world most productive glacier draining approximately 5.4% of the Greenland Ice Sheet [13]. Just south of the fjord a shallow area up to only 30 m deep is Store Hellefisk Banke, an area of very high production and known rich fishing grounds. As part of the INTAROS project, a high resolution model was set up for this area, with the main goal of modelling the primary production. Here we present the hydrodynamic part of the model. An orthogonal mesh varying in horizontal resolution from 2 km in the inner part to 15 km near the open boundary was constructed using JigSaw (http://sites.google.com/site/dengwirda/jigsaw). Bathymetry was interpolated from the 150x150 m resolved IceBridge BedMachine Greenland, Version 3” bathymetry (https://nsidc.org/data/IDBMG4), see figure 4. The model has 25 vertical layers, increasing in thickness from 10 m in surface to 50 m near the bottom. Open boundary forcings of velocities, water level, temperature and salinity was obtained from the HYCOM model provided by the Danish Meteorological Institute (DMI). 2D fields of meteorological data was also provided by DMI and used for free surface forcings. Meltwater run-off from Programme for Monitoring the Greenland Ice Sheet (PROMICE) was provided by the Geological Survey of Denmark and Greenland (GEUS) and used for freshwater input. The timestep in the model was 5 minutes and the hydrostatic hydrodynamics including advection and diffusion of salinity and temperature simulates 1 year in 2.5 hours on an off-the-selves desktop pc (4 core intel i7-6400, 3408 MHz). The model reproduces the tidal currents in the straits and the pumping of deeper water up on Store Hellefisk banke. To the right in figure 4, comparison of modelled salinity and salinity profiles from CTD measurements obtained from the International Counsil for the Exploration of the Seas (ICES) database are shown. The profiles are from the inner part of the Disko bay near the outlet of the Ilulissat ice fjord, and it can be seen that the model nicely reproduces the fresh surface water and the general salinity profile, although the deeper water is too fresh.
Surface particle tracks
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