Numerical simulation of ice cover of saline lakes

Abstract

A new version of 1D thermodynamic and hydrodynamic model LAKE 2.1 is presented. The model is supplemented with description of dynamics and vertical distribution of salinity in ice layer. Simulation results are compared to in situ and satellite data on water temperature and ice cover at Lake Uvs (Mongolia) from 2000 to 2015. We demonstrate that underestimation of mixed-layer depth by the model with standard k–ε closure during summer and autumn leads to significant shift of ice-on to earlier dates. If the effects of water salinity are neglected in the model, ice cover establishes 16–17 before the observed dates. This error is removed, if influence of salinity on water density and freezing point is included, still assuming the fresh ice. However, in this case, LAKE model underestimates the maximal winter ice thickness on average by ≈0.2 m. In turn, this discrepancy decreases an order of magnitude if dynamics and vertical distribution of salinity in ice are reproduced. Such an effect does not take place when using constant salinity value in ice.