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

Quantifying the regional and global exchange Of CO2 between the ocean and a tmosphere requires knowledge of the factors that affect CO2 gas transfer (e .g., wind speed) and the air-sea difference in partial pressure Of CO2 (PCO 2). A major uncertainty is the effect of short-term variability on airsea C O2 flux. Using high sampling frequency wind speed and PCO2 data collected d uring deployments of the autonomous CARbon Interface OCean Atmosphere (CARI OCA) buoy, we compare CO2 fluxes at different sampling frequency of wind sp eed (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 averag e values. This difference arises from the non-linear relationship between w ind speed and CO2 gas transfer coefficient, and a better representation of wind distribution at a higher frequency (i.e., hourly) of sampling. This fi nding has significant implications for determining regional and global air- sea CO2 fluxes, and understanding of the global carbon cycle.