The influence of short-term wind variability on air-sea CO₂ exchange

Nicholas R. Bates , Liliane Merlivat (1)

1 LODYC - Laboratoire d'océanographie dynamique et de climatologie

Quantifying the regional and global exchange of CO₂ between the ocean and atmosphere requires knowledge of the factors that affect CO₂ gas transfer (e.g., wind speed) and the air-sea difference in partial pressure of CO₂ (pCO₂). A major uncertainty is the effect of short-term variability on air-sea CO₂ flux. Using high sampling frequency wind speed and pCO₂ data collected during deployments of the autonomous CARbon Interface OCean Atmosphere (CARIOCA) buoy, we compare CO₂ fluxes at different sampling frequency of wind speed (i.e., hourly versus daily averaged). Air-sea CO₂ flux was up to three times greater if high frequency wind data was used rather than daily average values. This difference arises from the non-linear relationship between wind speed and CO₂ gas transfer coefficient, and a better representation of wind distribution at a higher frequency (i.e., hourly) of sampling. This finding has significant implications for determining regional and global air-sea CO₂ fluxes, and understanding of the global carbon cycle.

Mots clés: Oceanography: General: Climate and interannual variability (3309); Oceanography: General: Marine meteorology; Oceanography: Physical: Air/sea interactions (0312); Oceanography: Biological and Chemical: Carbon cycling

Domaines: Géophysique [physics.geo-ph]; Géophysique [physics.geo-ph]

Nicholas R. Bates, Liliane Merlivat. The influence of short-term wind variability on air-sea CO₂ exchange. Geophysical Research Letters, 2001, 28, pp.3281-3284. ⟨10.1029/2001GL012897⟩. ⟨hal-00772145⟩