Istanbul 5 th March 2010 Efficient downscaling to coastal sea using the unstructured finite volume model MIKE 3 – applications in the Ligurian Sea and for Danish Belts Jacob V Tornfeldt Sørensen, DHI MedGOOS Half-day Seminar 2010

Step I : Bathing water analysis Scenario modelling (LIP) Step II : Operational forecasting Ligurian coastal sea 3D model (in colaboration with INGV) Recent Experiences User : Agenzia Regionale per la Protezione dell'Ambiente Ligure (ARPAL)

Model forcing : MFS boundaries of T, S, u, v and surface elevation Tides and inverse barometer effect imposed at the open boundaries Atmospheric forcing from BOLAM Ligurian coastal sea 3D model Recent Experiences

500 km Fehmarnbelt Fixed Link Recent Experiences

The largest fixed link in Europe 20 km Bridge or tunnel billion EUR Danish-German agreement September 2008 Excepted opening in 2018 Denmark Germany Recent Experiences

Blocking Water Exchange of the Baltic Sea Water Exchange of the Baltic Sea Ecology of the Baltic sensitive to salinity Ecology of the Baltic sensitive to salinity Cod Fishery Cod Fishery DarssBothnian Bay Stolpe Channel Gotland Deep Bothnian Sea Baltic Sea Environmental Concern, (Permanent Effects)

Dredging Spill Shading of Macro Algae Shading of Macro Algae Impact on Mussels Impact on Mussels Fish Migration Fish Migration Birds Birds Marine Mammals Marine Mammals Environmental Concern, (Temporary Effects)

Key Issues Boundary conditions Internal Downscaling Consistancy calibration of coarse model data Downscaling

Key Issues Boundary conditions –Regional basin and mesoscale circulation –Tidal elevation and inverse barometer effects –Numerical implementation (e.g. Flather, interpolation constraint) Downscaling

MIKE 21 model setup Mercator Ocean mesoscale model DHI Gulf of Mexico model Downscaling

Key Issues Internal Downscaling –Numerical method allowing gradual increase in resolution (e.g. flexible mesh finite volume) –Resolution and bathymetry prererably consistent to coarse model at and near open boundary –Include model features of importance for local scale modelling (e.g. mass conserving F/D, structures, wave current interaction and process modules) Downscaling

Ligurian coastal sea 3D model Downscaling ~ 500m Resolusion ~ 500m MIKE 3 HD FM Bathymetry consistency Consistent resolution Smooth downscaling

Downscaling Increased flow resistance and increased mixing

Downscaling Combination of: - Field measurements - Physical model experiments - Detailed CFD analysis CFD will supplement and extend the data from the physical model experiments Parameterisation of flow resistance and mixing

Local high resolution oceanographic MIKE 3 FM model

Downscaling additions

Skillful regional scale models exists Basic downscaling technology and methodology exist Every case still needs careful analysis and hard work Streamline approach via user interface Advance local scale data assimilation Further improvement of boundary condition formulation Improved computational performance Conclusion and next steps

Thank you for your attention Further information: