In the paper, the results of eddy-resolving numerical simulation of convection generated by inhomogeneous heating of water column by solar radiation in an ice-covered shallow lake (the factor of wind impact on the water surface is excluded). The calculations have been performed using the Implicit LES method for different values of the extinction coefficient, which defines the degree of attenuation of solar radiation in the water column. An analysis of the three-dimensional flow structure, the time evolution of temperature and velocity pulsations was carried out, and the increments of the lower boundary and the temperature of the convective mixed layer were calculated depending on the incoming heat. The results obtained shed light upon the nature of the processes occurring in the type of lakes under consideration, in particular, to identify the influence of water transparency on the convective mixing process.