Tendances et variabilité des caractéristiques des vagues dans le Golfe de Gascogne de 1958 à 2001
Charles, Elodie ; Idier, Déborah ; Thiébot, Jérôme ; Le Cozannet, Gonéri ; Pedreros, Rodrigo ; Ardhuin, Fabrice ; Planton, Serge
Climate change impact on wave conditions is of many concerns, regarding off-shore and coastal hazards. The present paper investigates the wave climate multi-decadal trends and inter-annual variability in the Bay of Biscay during the past decades (1958-2001). Wave fields are computed with a wave modelling system based on WAVEWATCH III code and forced by ERA-40 reanalysis wind fields. A solid validation of the wave model and a fine spatial resolution (10 km in the Bay of Biscay) allow the use of computed wave fields in the analysis of wave climate trends and variability in deep and intermediate water depths. Examination of seasonal mean and extreme wave conditions highlights no significant trend in the Bay of Biscay, except for summer wave fields from 1970 to 2001, exhibiting a significant wave height increase of about 0.5 cm/y at Biscay buoy. The high inter-annual variability of wave conditions in the Bay of Biscay is studied regarding its relationship with northern hemisphere teleconnection patterns. A strong correlation of wave characteristics with the North Atlantic Oscillation and the East Atlantic pattern indices is underlined, as well as with other teleconnection patterns, appearing to be linked to certain seasonal wave conditions. Most of these relations can be explained by the atmospheric circulation anomalies associated to teleconnection patterns.
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