Representing and evaluating the landscape freeze/thaw properties and their impacts on soil impermeability: Hydrological processes in the community land model version 4

摘要: [1] Snow cover at high latitudes is an excellent natural insulator that can maintain the underlying ground a higher temperature than overlying atmosphere. Soil impermeability usually varies when snow accumulates, which closely related to soil and landscape freeze/thaw status. How affects frozen fraction how this regulates hydrological processes in cold regions have not been fully assessed quantified. In order understand these processes, study performed series of experiments by using Community Land Model version 4 (CLM4). We first simulated top-soil-layer ice, canopy ice calculate fraction, was evaluated based on Special Sensor Microwave/Imager (SSM/I) observed earth system data record (FT-ESDR) two selected latitudes. Then parameterizations were validated against various situ satellite observations. The results suggest following: (1) compared SSM/I FT-ESDR, CLM4 capture overall status north 60°N boreal winter spring; (2) as approaches unity, CLM4-simulated mainly controlled amount, resulting step changes between FT-ESDR fractions; (3) most regions, timing spring runoff simulations improved reducing impermeable area regions.