Young Sound is a sill fjord located in north-east Greenland. It is approximately 90 km long, max. 8 km wide, 325 m deep at the deepest point and the sill in the entrance is 45 m deep. The inner branch is called Tyroler fjord. The fjord is characterised by a short ice free period (July-Sept) with a high freshwater input, mainly from glacial melt. The Zackenberg research station is located on the northern shore of Young Sound and hence a monitoring program of Young Sound has been carried out during the summer period.

A nonhydrostatic hydrodynamic setup was made using a computational mesh, which varies in horisontal resolution from 230 m at the sill to Young Sound and Tyroler fjord to 450m at the open boundary. In the vertical, the model has 54 layers: á 1.5 m surface layer which veries in thickness to accomodate the free surface, then 5 layers of 0.5 m, 6 layers of á 1.0 m , 10 layers of 2.0 m, 5 layers of 5.0 m and the remaining 21 layers are 10 m thick. The model has a total of 525600 computational cells

Meteorological forcings were interpolated from WRF model version 3 output (doi.org/10.1016/j.atmosenv.2021.118631) . The model includes ice cover as a forcing, obtained from CMEMS https://doi.org/10.48670/moi-00123 and open boundary forcings, interpolated from HYCOM model output (doi.org/10.48670/moi-00007). Temperature and salinity on the opne boundary, were adjusted with measured CTD data from the GEM monitoring program (g-e-m.dk/). Fresh water runoff obtained was added to the model, which was obtained from the PROMICE project (doi.org/10.22008/FK2/XKQVL7).

The Young Sound setup was run for all of 2014, for which a total of 181 CTD profile on 35 different positions was measured in the period from medio July to beginning og October. Here CTD profiles from 4 campains (late July, early August, mid September and early October) are plotted on a transect of model output through the length of the fjord. The transect is shown on the map to the right.

For salinity, the plots show that the model reproduces the characteristic thin fresh surface layer in July, which is eroded during the summer, to for a more gradual salinity stratification in October. The model over estimates the surface temperature and is not able to reproduce the very sharp vertical gradients.