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Accueil > Actualités > Séminaires > Séminaires 2013

Vendredi 21 juin 2013, 11h00 LEGI salle de Séminaire

Angel Ruiz-Angulo, Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México

Titre/Title :
Internal wave observations in the Petacalco canyon, Mexico

Contact :
Jan-Bert Flor (équipe Meige)

Résumé/Abstract :
This study presents the observation of large amplitude internal wave activity, in the order of 50 [m], near the head of the Petacalco submarine canyon in the Mexican Pacific. The waves propagate with periods similar to the M2 tide component and the observations show that temperature rates of change reached up to 10 [°C / h]. The presence of this canyon enhances the turbulent mixing. The slopes of the canyon’s wall trap the waves as they propagate up-canyon, as they travel along the axis the become more energetic. Based on linear wave theory along the axis slope of the canyon there are regions where the critical refraction is reached, suggesting that there are regions favorable for wave breakage. This process enhances mixing of cold water masses with shelf hot water. This exchange is more permanent than only internal waves transporting nutrients as they propagate. Trough this mechanism, the mixed waters remain in the neighborhood for longer periods of time resulting on an alternative upwelling mechanism. Additionally, this investigation suggests that the upwelling mechanism cannot be due to Ekman transport since the winds in the region of study are very weak and do not support wind driven upwelling transport.