Spring Thermal Bar Formation in a Water Reservoir with a Complex Bottom Relief (for Lake Ladoga as an Example)

Abstract

In this study, the dependence between the spring thermal bar (TB) propagation velocity in a fresh water reservoir and the morphometric parameters of its bottom is obtained via mathematical modeling. Characteristic intervals of TB propagation velocities in reservoirs for different depths and bottom inclinations are found. It is demonstrated that the main factor that affects the TB lifetime is the reservoir depth. The influence of the relative air humidity and solar radiation flux on the spring TB propagation velocity is estimated. Isolines of space—time variability of the TB location in the water area of the reservoir are constructed using the simulations and the quantitative parameters of Lake Ladoga bottom relief. Satisfactory agreement between the simulated data and the field observations is achieved.