Radon Profiles in the Sea: A Measure of Air-Sea Exchange

A review of factors affecting air-sea gas exchange suggests that the exchange rate may be more dependent upon the rate of sea surface renewal than upon the boundary film thickness. In either case wind velocity dominates the exchange rate. Both the gas exchange rate and the rate of vertical mixing can be evaluated by measurements of the radon profile in the upper 100 m of the water. Radon is extracted from eight depths in the profile using a set of continuous flow extractors which efficiently remove radon and other dissolved gases at flow rates of 1-2 1/min. Radon measurements in the Atlantic suggest gas exchange rates corresponding to a transfer velocity of 0.005 to 0.010 cm/sec (film thickness 10-20 μ) at wind speeds of 10-20 knots.