Assessing the skill of a numerical model of the circulation in the Oslofjord
The Oslofjord is a complex estuary which connects several towns and a small city (Oslo!) to the Skagerrak and adjacent ocean regions (the Baltic and the North Sea). Modeling the transport and dispersion of e.g. pollutants (oil spills!) in the fjord is of crucial importance to the population around the fjord. But we are still uncertain about how good the existing numerical models of the fjord circulation in fact are.
In this project we will therefore compare a state-of-the-art numerical model of the Oslofjord to various observations from the fjord. The focus will be on studying currents, both at the sea surface and at depth, using both Eulerian (fixed points in space) and Lagrangian (floataing objects) techniques.
The work will be done in collaboration with the Norwegian Meteorological Institute (MET) and the Norwegian Institute for Water Research (NIVA). We will focus on observing and understanding the exchanges between the inner and outer parts of the fjord, exchanges that rely on a combination of wind and tidal forcing and are also impacted heavily by the shape of the coastline and the bottom topography.
Of particular interest is the ability of the model to reproduce observed exchanges of deep water between the inner and outer fjord since this impacts the oxygen, nutrient and pollution levels in the inner fjord. A large database of historical observations will be used, but we will also collect new observations via existing routine monitoring programmes and also with one or two dedicated cruises with UiO's research vessel F/F Trygve Braarud.
Deep currents will be observed with moored acoustic instruments (ADCPs) while surface currents will be observed with Lagrangian drifters deployed from T. Braarud.