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Earlier modelling studies have shown the difficulty of accurately simulating snowmelt infiltration into frozen soil using the hydraulic model approach. Comparison of model outputs and field measurements have inferred the occurrence of rapid flow even during periods when the soil is still partly frozen. A one-dimensional, physically based soil water and heat model (SOIL) has been complemented with a new two-domain approach option to simulate preferential flow through frozen layers. The ice is assumed to be first formed at the largest water filled pore upon freezing. Infiltrating water may be conducted rapidly through previously air-filled pores which are not occupied by ice. A minor fraction of water is slowly transferred within the liquid water domain, which is absorbed by the solid particles. A model validation with field measurements at a location in the middle-east of Sweden indicated that the two-domain approach was suitable for improving the prediction of drainage during snowmelting. In particular, the correlation between simulated and observed onset of drainage in spring was improved. The validation also showed that the effect of the high flow domain was highly sensitive to the degree of saturation in the topsoil during freezing, as well as to the hydraulic properties at the lower frost boundary regulating the upward water flow to the frozen soil and ice formation. 相似文献
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EVA ENGBLOM PER-ERIK LINGDELL LUDMILA MARVANOVA AGNES MULLER-HAECKEL 《Polar research》1986,4(1):47-51
Nineteen species of aquatic hyphomycetes are reported from stream foam in southern Greenland. This extends the number of species known from the arctic regions. Thirteen of these species have also been collected in Swedish Lapland. Thus, despite different bank vegetation, the species pattern of both areas show a more than 50% similarity. 相似文献
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