Simulation of soil profile heat dynamics and their integration into hydrologic modelling in a permafrost zone

To improve hydrologic modelling in permafrost zones, we present a new hydrological modelling approach to simulate ground thaw/freeze processes and the consequent contribution to the hydrologic response. We apply several techniques to simplify the differential equations of heat transfer in soil profiles, from which we derive an analytical solution that accounts for phase changes in soil and includes specific approaches for heat transfer and phase-dependent soil and snow conductivity. Use of soil horizon physical properties as the model parameters allows robust assessment relative to landscape characteristics. Following integration of these methods within the Hydrograph hydrological model, verification was conducted against a time series of soil temperature observed at the Kolyma Water Balance Station in the continuous permafrost zone of northeast Russia