Measurements of gas exchange and momentum transfer in a circular wind-water tunnel

Abstract

Gas exchange and momentum transfer have been studied by means of a small circular wind-water tunnel. Gas transfer velocity and friction velocity first grow linearly with wind speed. At a critical wind speed, with the onset of rough waves, both increase abruptly. The experiments clearly show the enhancement of air-water exchange processes by waves. Experimental conditions were varied-nitrogen/carbon dioxide atmosphere, temperature, circulation of water unconfined/confined by a dam-and found to influence gas exchange. This, and the differing results of various authors demonstrate that gas exchange is not a function of wind speed alone, nor of friction velocity, but that further parameters, such as wave spectra, have to be considered as well.