The non-linear influence of wind-speed variability on gas transfer in lakes

Abstract

By combining the Weibull wind-speed distribution with commonly employed trilinear and power-law expressions for the dependence of the gas transfer velocity on wind speed, analytical expressions for the mean value of the transfer velocity are obtained. These expressions predict the non-linearity of the dependence of gas transfer velocity on wind speed to be responsible for an increase in the mean transfer velocity which will normally not exceed 100% of the value obtained when non-linear wind effects are neglected. In the specific case of the winter oxygenation of a typical subalpine Swiss lake (Aegerisee), the commonly employed trilinear and power-law expressions are found to underestimate the mean O2 transfer velocity considerably. -from Authors