A new study evaluated the accuracy of the WAM wave model in the Helsinki archipelago by a comparison with wave buoy measurements done at Harmaja. Even though the model performance was mostly accurate, some possibilities for further development were identified in the study.
FMI's numerical wave model WAM models the waves accurately in the open sea. However, near the shore new challenges for the model are set by the complex shoreline and the numerous small islands.
The greatest challenge for the model was to correctly capture the wave field generated by south-westerly winds blowing over the peninsula of Porkkala. The wave field was found to consist of both waves that are limited by the distance to the peninsula and longer waves that are propagated around it.
For the south-westerly winds the model generated too high waves with respect to the strength of the wind. The performance was enhanced when weaker wind were provided to the model, but this can lead to inaccuracies at other locations than Harmaja and can therefore not be considered to be a permanent solution.
The City of Helsinki's new wave buoy outside of Suomenlinna will surely aid in the continued development of the wave model, which has been proven to be a formidable tool despite of its slight restrictions. The newest application is a new operational forecast for the location of the new wave buoy that is located inside the archipelago near Suomenlinna (visit http://meri.hel.fi).
Research Scientist Jan-Victor Björkqvist, tel.: +358 29 539 2187, firstname.lastname@example.org
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