Development and evaluation of temperature-induced variable source area runoff generation model

In permafrost regions, temperature and precipitation play decisive roles in hydrological processes. Soil freeze-thaw cycles in the active layer cause the runoff generation process to show multiple mechanisms and seasonal alternating patterns. In this study, based on the precipitation-runoff modeling system implemented in the Java modeling framework Object Modeling System (PRMS-OMS), we developed a runoff generation model with temperature-induced variable source area (TVSA) for permafrost regions by introducing an active layer parameterization scheme, an active layer freeze-thaw module, a glacier module, and the sub-permafrost groundwater module. The TVSA model was calibrated and validated using field observations in Fenghuoshan (FHS), a typical permafrost watershed, and Tuotuohe (TTH), a typical permafrost-glacier catchment, on the Qinghai-Tibet Plateau (QTP). During the calibration period, parameters related to the thermal conditions of the active layer and runoff processes were calibrated using the observed freeze and thaw depth data and the discharge data. For the validation period, the model successfully reproduced the freeze-thaw processes (average root mean squared error = 0.205 m) and discharges (FHS, Nash-Sutcliffe efficiency coefficient (NSE) = 0.99; TTH, NSE = 0.85). The TVSA model is a powerful tool for the system identification of variable source runoff generation processes and the associated physical mechanism under temperature control in permafrost basins; additionally, the model accurately reproduces hydrological processes and the associated response to climate change.

Automated summary

In this study, a temperature-induced variable source area (TVSA) runoff generation model was developed for permafrost regions. The model was calibrated and validated using field observations, and it successfully reproduced freeze-thaw processes and discharges with high accuracy.