ИСТИНА

Lakes are an important source of atmospheric methane and carbon dioxide, as is evidenced by numerous field measurements. Thus, it is necessary to gain a comprehensive understanding of physical and biochemical mechanisms responsible for lake methane emissions, that would facilitate prediction of these fluxes in future climate. As the main research tool we use the lake numerical model LAKE (Stepanenko et al., 2011). One of the most important parts of this model is a parameterization of gas exchange at the air-water interface, which governs the magnitude of methane diffusive flux. The most incertain element of this parameterization is the gas transfer velocity, k, that is determined by a complex of insufficienly understood physical processes. These processes characterize a state of the atmospheric surface layer above the water and the top thin layer of the lake. In current study, we implement three parameterizations of transfer velocity in the LAKE model: empirical relationship of k with wind speed (Cole J. and Caraco F., 1998), film stagnant model (Whitman, 1923), and the surface renewal model (Higbie, 1935). The LAKE model is then applied to the lake Seida (Republic of Komi), and its output is compared to measurement data, performed by University of Eastern Finland. Further, we carry out an analysis of differences between the model results using the three gas exchange parameterizations.