Air-sea gas exchange into the millennium: Progress and uncertainties

The current status of research into air-water gas exchange is reviewed. Som e relevant basic concepts are re-examined within the context of current pro gress towards parameterization of the air-sea gas exchange process using mo dels and data from wind-tunnels, and the interpretational difficulties that still persist with these approaches are identified and discussed. Subseque ntly, field measurements of air-water gas exchange are reviewed, with key d evelopments highlighted, in particular, important recent advances in the us e of micrometeorological and chemical tracer-based techniques of measuremen t. Results obtained with these methods are summarized and compared with lab oratory wind-tunnel-based measurements, in order to identify some outstandi ng gas exchange issues still to be resolved. In the light of these, the pot entially important roles played by a variety of physical, chemical and biol ogical forcings are considered and some likely fruitful avenues for future research are outlined for this important area of global science.