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The paper presents application of the geomorphologic and hydrodynamic models for overland flow simulation in small mountainous basins. For GIUH description has been used two-parameters gamma model. Its parameters were estimated from the IUH characteristics qp (peak flow) and tp (time to peak), which were determined in dependence on basin geomorphology and flow velocity. Determination of flow velocity in function of basin geomorphological characteristics and excess rainfall intensity allowed description of the overland hydrograph with the whole family of GIUHs. Starting from the principle of the kinematic wave equations has been established the dimensionless hydrograph. Having determined the two basical parameters, QM (maximum flow) and t, (concentration time) the dimensionless hydrograph model has been used for overland hydrograph simulation in natural, ungauged basins.
In connection with undertaking works on the physically based basin model it appeared indispensable organization of the special research basin. The fundamental task of the basin is collecting the data necessary for calibration as well as for verification of the integral model and its particular processes sub-models. In general the measurement data required for these purposes are not attainable in classic experimental and representative basins. Achievement of them requires organization of the special measurement programme. The experimental basin area is equal to 0,07 km². The stream is the right inflow of the Vistula River, 12 km downstream of Płock. In the paper have been described the basical research tasks of the basin, physiographic characteristics of its area and the measurement programme. In the basin have been selected two typical quasi-homogenous unit areas (in the piny forest and on the fallow area), which were used for the verification of the vertical water circulation model.
In the paper has been described problem of freezing and thawing of soil as well as has been adapted a mathematical model of infiltration into seasonally frozen soil, making use of the coupled heat and moisture transport equations. Methods for determining the hydrophysical soil properties (hydraulic and thermal conductivities, matric potential, heat capacity) have been reviewed and a method for estimating the parameters related to phase transition has been suggested. The mathematical model has been verified in the experimental basin in Murzynowo.
In the paper has been described the model structure of the vertical water circulation in the unit basin represented by the quasi-homogenous column containing the soil monolith overgrown by the forest phytocenosis with well formed four-layered structure. The model describes the processes of the vertical mass and energy exchange on the contact of the atmosphere, biosphere and pedosphere /interception, evapotranspiration and soil moisture variation under the influence of the infiltration and evapotranspiration processes/. All the hydrological processes have been described with the mathematic physics and parameters were determined by the direct measurements in the field. The verification of the component models has been performed in the experimental basin in Murzynowo near Płock on the data from the observational period from 17 to 21 July 1987. The verification has been carried out in two phases. The basis of the I verification was the comparison of the measured and computed feeding values of the forest ground. In the II phase the basis of the verification was comparison fo the measured and simulated soil moisture profiles in the unsaturated zone. The achieved results may be estimated as fairly good, but this problem requires further investigations, especially in the experimental field.
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