CO₂ fluxes in the tropical Atlantic during FOCAL cruises

Abstract

CO2 partial pressures in the atmosphere and in surface seawater have been measured in the equatorial Atlantic Ocean during Programme Français Océan‐Climat en Atlantique Equatorial cruises extending from July 1982 to August 1984 along the 4°W, 22°W, and 35°W meridians. Gas transfer coefficients based on recently reported field data combined with information deduced from wind tunnel experiments are used to compute the CO2 fluxes. The global mean net flux between 5°N and 5°S is equal to 1.05 mmol m−2 d−1 and is from the ocean to the atmosphere. The escape of CO2 increases strongly from the east to the west and is always lower in the north than in the south. The importance of wind speed, pCO2 in atmosphere, PCO2 in surface seawater, and temperature on the flux variability is discussed. The relative influence of the equatorial upwelling on one hand and of the advection and warming of surface waters on the other hand is studied in order to explain high partial pressure in seawater.

A new method for continuous measurements of oceanic and atmospheric N<sub>2</sub>O, CO and CO<sub>2</sub>: performance of off-axis integrated cavity output spectroscopy (OA-ICOS) coupled to non-dispersive infrared detection (NDIR)

“…10). These results are consistent with observations reported by previous studies in the eastern tropical Atlantic Ocean (Andrié et al, 1986;Bakker et al, 1999;Lefèvre et al, 2008). A strong enhancement in surface f CO 2 was observed during the second equatorial section (lower right panel on Fig.…”

Variability and trends of carbon parameters at a time series in the eastern tropical Atlantic

“…It is interesting to note that Goyet et al (1998) did not detect any change of seawater fCO 2 when comparing the WOCE A15 data with the FOCAL cruise made 10 years earlier (Andrie´et al, 1986) but the continuous increase of atmospheric fCO 2 led them to conclude to a weaker source of CO 2 along 198W. The same mechanism is observed here.…”

Short-term changes in the partial pressure of CO₂ in eastern tropical Atlantic surface seawater and in atmospheric CO₂ mole fraction

“…The measurements of COz partial pressures in air (pCOz) and in seawater (PCOz) were carried out by infrared absorption with two ADC 225 MK3 analyzers (Oudot and AndriC, 1986;Andrit et al, 1986;Oudot et al, 1987). Air was taken at the upper bridge of the vessel which was about 2 00…”