闪电

The accurate quantification of infiltration processes in cold regions is essential for predicting hydrological responses to climate change and developing effective water management strategies. Current infiltration models are developed for stable, temperate conditions and constant soil properties, which contrast sharply with the thermal and hydraulic conditions in freeze-thaw environments. This study proposed a Horton-RCCC formula specifically designed for the freeze-thaw environment in cold regions, which are achieved by several terms of innovation as follows. A large-size undisturbed soil sampling and restoration method to enable laboratory simulation of soil freeze-thaw processes. The soil freeze-thaw state is innovatively described using the ratio of current freeze-thaw depth to maximum freeze-thaw depth. The calculation equations for soil water initial infiltration rate and stable infiltration rate are developed, shifting from the traditional approach of using a single parameter set for entire watersheds and improving distributed characterization of soil infiltration capacity under varying underlying surface conditions. The Horton-RCCC formula is calibrated and validated in permafrost and seasonally frozen ground regions. In complete thawing stage, the Horton-RCCC formula demonstrates comparable accuracy with that of Horton equation on a condition of zero slope, and shows its advantage to calculation infiltration under sloped conditions. In freeze-thaw period, the Horton-RCCC formula effectively addresses the dynamics of underlying surface infiltration conditions, and shows a significant improvement in accuracy. This formula breaks away from the conventional research paradigm of directly applying infiltration formulas for temperate conditions, could stimulate improvements in hydrological modeling, water resource management and climate change adaptation in cold regions.