Merlivat¹, L., M. Gonzalez Davila², J.M. Santana-Casiano² and J. Boutin¹

¹Laboratoire d’Oceanographie Dynamique et de Climatologie, Paris, France and ²Universidad de Las Palmas de Gran Canaria, Las Palmas, Spain, Tel: 33144277072, Fax: 33144277159, E-mail: merlivat@lodyc.jussieu.fr

Spatial and temporal variability of the distribution of pCO₂ and dissolved inorganic carbon at the sea surface measured by CARIOCA drifters in the North East Atlantic Ocean during the POMME project

Four CARIOCA drifters were launched in February 2001 during the first campaign of the POMME project. A time series of data, measured between February and August 2001, has shown that in winter conditions the ocean surface in the POMME area is undersaturated for atmospheric CO₂. An additional decrease of surface pCO₂ is observed from early April as the result of carbon consumption to produce organic matter during the spring. The overall decrease of inorganic carbon at the sea surface between April and June, close to 60 mmoles per kg, is caused mainly by a small number of sporadic events which last only a few days. In some cases, these events are associated with the presence of cyclonic mesoscale structures.

The spatial extrapolation of the lagrangian buoys’ measurements to a region of the North Atlantic, between 36°N and 46°N and 12°W to 22°W, has been made using satellite measurements (Quikscat wind speed, AVHRR SST), and empirical relationships between pCO₂ and SST established monthly with the buoy’s measurements. Over the February-August period, the mean absorbed CO₂ flux is equal to -4.4 mmoles/ m²/ day.