A numerical study of the thermal bar in shallow water during the autumn cooling

The article presents numerical simulation of the autumnal thermal bar dynamics on the example of the Selenga River shallow water in Lake Baikal. Hydrophysical and atmospheric conditions of the object under study in autumn are taken into account. The influence of river inflow (runoff current and water mineralization) and wind impact on the thermal bar behavior are evaluated. The numerical modeling analysis demonstrates that in the early stage of the thermal bar development, the most significant for convection is the momentum of the river inflow. However, with the distance increase between the thermal bar and the river mouth, the role of the river mineralization and wind stress also increases. Highly mineralized inflow waters have the largest impact on thermohydrodynamic processes in shallow waters under calm weather conditions. Wind action on the lake surface may lead to the deviation of the line of convergence of water masses from to the 4 degrees C isotherm. Moreover, prolonged wind activity may result in the destruction of the thermal bar front and vertical thermal homogeneity across the entire shallow water area. (C) 2019 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved.