La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Variability of the gas transfer velocity of CO(2) in a macrotidal estuary (the Scheldt)
Auteurs :	A. V. Borges, Auteur ; J. P. Vanderborght, Auteur ; L. S. Schiettecatte, Auteur ; F. Gazeau, Auteur ; S. Ferron-Smith, Auteur ; B. Delille, Auteur ; M. Frankignoulle, Auteur
Type de document :	Article
Dans :	Estuaries (27(4) AUG 2004)
Article en page(s) :	593-603
Résumé :	We report a large set of 295 interfacial carbon dioxide (CO(2)) flux measurements obtained in the Scheldt estuary in November 2002 and April 2003, using the floating chamber method. From concomitant measurements of the air-water CO(2) gradient, we computed the gas transfer velocity of CO(2). The gas transfer velocity is well correlated to wind speed and a simple linear regression function gives the most consistent fit to the data. Based on water current measurements, we estimated the contribution of water current induced turbulence to the gas transfer velocity, using the conceptual relationship of O'Connor and Dobbins (1958). This allowed us to construct an empirical relationship to compute the gas transfer velocity of CO(2) that accounts for the contribution of wind and waiter current. Based on this relationship, the spatial and temporal variability of the gas transfer velocity in the Scheldt estuary was investigated. Water currents contribute significantly to the gas transfer velocity, but the spatial and temporal variability (from daily to seasonal scales) is mainly related to wind speed variability.

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