For shallow lakes, ice mass balance is largely dominated by thermodynamic processes. The heat flux from lake water plays a critical role for ice growth and melting. In this study, we applied a numerical thermodynamic lake model to investigate the sensitivity of the lake ice mass balance to the lake heat flux during the growth and melting periods. Several groups of modelling experiments forced by simplified climatological weather data have been carried out. Two sites, Lake Wuliangsuhai in Inner Mongolia, China’s arid region and Lake Orajärvi in snowy Finnish Lapland, were investigated. Lake heat flux affects inversely proportional maximum ice thickness followed by ice break-up date. The solar radiation and surface albedo complicate the effect of lake heat flux on lake ice mass balance during melting season. With heavy snowfall, the increase of lake heat flux adds on the formation of granular ice but reduces the formation of columnar ice. Under climatological weather conditions, the ice cover winter seasonal mean lake heat flux were 14 W·m−2 and 4 W·m−2 in Lake Wuliangsuhai and Lake Orajärvi, respectively.Peer reviewe
