The simulation of runoff from small catchments in the permafrost zone by the SWAP model

Parameter Optimization for Simulating Runoff from Highlatitude River Basins Using Land Surface Model and Global Data Sets

“…During the last 10 years, different versions of SWAP were validated against observations including characteristics both related to energy balance or thermal regime of SVAS (sensible and latent heat fluxes, ground heat flux, net radiation, upward longwave and shortwave radiation, surface temperature, soil freezing and thawing depths) and related to hydrological cycle or water regime of SVAS (surface and total runoff from a catchment, river discharge, soil water storage in different layers, evapotranspiration, snow evaporation, intercepted precipitation, water table depth, snow density, snow depth and snow water equivalent, water yield of snow cover). The model validations were performed for "point" experimental sites and for catchments and river basins of different areas (from 10 -1 to 10 5 km 2 ) on a long-term basis and under different natural conditions (e.g., Gusev & Nasonova 1998, 2003Gusev et al, 2006a;Boone et al, 2004). The results have demonstrated that SWAP is able to reproduce (without calibration) heat and water exchange processes occurring in SVAS under different natural conditions adequately, provided that input data of high quality are available.…”

“…The last version of SWAP treats the following processes: interception of liquid and solid precipitation by vegetation; evaporation, melting and freezing of intercepted precipitation, including refreezing of melt water; formation of snow cover at the forest floor and at the open site during the cold season; partitioning of non-intercepted precipitation or water yield of snow cover between surface runoff and infiltration into a soil; formation of the water balance of aeration zone including transpiration, soil evaporation, water exchange with underneath layers and dynamics of soil water storage; water table dynamics; formation of the heat balance and thermal regime of SVAS; soil freezing and thawing. The model can be applied both for point (or grid box) simulations of vertical fluxes and state variables of SVAS in atmospheric science applications (Gusev & Nasonova, 1998) and for simulating streamflow at different scales -from small catchments to continental-scale river basins located in different natural conditions (Gusev & Nasonova, 2000, 2003Boone et al, 2004;Gusev et al, 2006a). In the case of a small river basin (up to the order of 10 3 -10 4 km 2 ), a kinematic wave equation is used to simulate runoff at the basin outlet.…”

“…This mostly concerns precipitation due to its complicated stochastic nature resulting in the great problem of estimating area averages from point measurements. Incoming fluxes of shortwave and longwave radiation were not measured at meteorological stations, they were derived from standard meteorological observations using techniques, described in Gusev et al (2006a). Interpolation of meteorological observations to the centers of grid boxes was performed using the kriging procedure (Globus, 1987).…”

“…However, as a rule, they were derived under milder climate conditions (compared to Arctic and sub-Arctic climate) and their application to the regions with a severe climate results in strong biases (Gusev et al, 2006a). At the same time the sensitivity of snowmelt-driven streamflow to incoming longwave radiation is rather high, because this radiation greatly influences the rate of snow processes.…”

Application of a technique for scenario prediction of climate change impact on the water balance components of northern river basins

“…Then the obtained clear sky radiation is adjusted for the total cloudiness . Incoming longwave radiation was estimated by empirical relations using observed data on air temperature at a height of 2 m and cloudiness (Gusev et al, 2006a).…”