ИСТИНА

The one-dimensional model LAKE simulates thermohydrodynamics and biogeochemistry of enclosed water body and underlying soil. The model includes the processes of vertical heat transfer taking into account the penetration of shortwave radiation in a lakes (Heiskanen et al., 2015), ice, snow and underlying soil (bottom sediments). The model provides the possibility of calculating the evolution of the ice layer at the bottom. The equations of the model are formulated for quantities averaged over the horizontal section a reservoir, which leads to an explicit account of the exchange of momentum, heat, and dissolved gases between the aqueous medium and the sloping bottom. In the water column, k-ε parametrization of turbulence is utilized, and the equations of motion take into account the barotropic pressure gradient (Stepanenko et al., 2016). The model also describes the vertical diffusion of dissolved gases (CO2, CH4, O2), as well as their bubble transfer, methane oxidation, photosynthesis and processes of oxygen consumption. Parameterization of methane production in the bottom sediments is included, and for the case of thermokarst lakes, an original formulation for the production of methane at the lower boundary of the thawed soil (talik). Tha capability of the model to reproduce the thermal and ice conditions of a large number of lakes in contrasting climatic conditions has been tested, including model intercomparison experiments within the project LakeMIP (Lake Model Intercomparison Project, Stepanenko et al., 2010; Stepanenko et al., 2013; Stepanenko et al., 2014). References Heiskanen, J. J., I. Mammarella, A. Ojala, V. Stepanenko, K.-M. Erkkilä, H. Miettinen, H. Sandström, W. Eugster, M. Leppäranta, H. Järvinen, T. Vesala, and A. Nordbo, 2015. Effects of water clarity on lake stratification and lake-atmosphere heat exchange. J. Geophys. Res. Atmos., 120, 7412–7428. doi: 10.1002/2014JD022938. Stepanenko, V.M. et al., 2010. First steps of a Lake Model Intercomparison Project. Boreal Environment Research, 15, pp.191–202. Stepanenko, V. M., Martynov, A., Jöhnk, K. D., Subin, Z. M., Perroud, M., Fang, X., Beyrich, F., Mironov, D., and Goyette, S., 2013: A one-dimensional model intercomparison study of thermal regime of a shallow, turbid midlatitude lake, Geosci. Model Dev., 6, 1337-1352, https://doi.org/10.5194/gmd-6-1337-2013 Stepanenko, V., Joehnk, K.D., Machulskaya, E., Perroud, M., Subin, Z., Nordbo, A., Mammarella, I., Mironov, D., 2014: Simulation of surface energy fluxes and stratification of a small boreal lake by a set of one-dimensional models, Tellus A, 66, 21389, http://dx.doi.org/10.3402/tellusa.v66.21389 Stepanenko, V., Mammarella, I., Ojala, A., Miettinen, H., Lykosov, V., and Vesala, T., 2016: LAKE 2.0: a modelfor temperature, methane, carbon dioxide and oxygen dynamics in lakes, Geosci. Model Dev., 9, 1977-2006, https://doi.org/10.5194/gmd-9-1977-2016