A Conceptual Model of Soil Moisture Movement in Seasonal Frozen Unsaturated Zone
Conceptual model is considered as one of the crucial and essential methods for scientific research on cold region hydrology. However, graphical conceptual model that integrates with a variety of influencing factors and specializes in describing soil moisture dynamic in seasonal frozen unsaturated zone has never occurred in any related researches, due to which the study on mechanism of frozen soil moisture movement has been delayed in a certain degree. Firstly, three stages of freezing and thawing process are divided in this article to serve for the further study in seasonal frozen unsaturated zone, which respectively are: the Stage of Freezing (Instable Freezing Stage and Stable Freezing Stage), the Stage of Thawing (Instable Thawing Stage and Stable Thawing Stage) and the Stage of Freeze-free. Secondly, based on different stages above, three characteristics and the relationships are analyzed, which include freeze-thaw-action and groundwater table, freeze-thaw-action and groundwater storage, freeze-thaw-action and soil surface evaporation. Thirdly, referred to related theories (Frozen Soil Hydrology and Snow & Ice Hydrology) and the construction of watershed model in warm regions, a whole set of graphical conceptual model and corresponding symbolic model have been built with freezing and thawing process as x-axis (time coordinate) and both soil frozen depth and different parameters as double y-axis. The different parameters include groundwater depth, soil water moisture rate and soil surface evaporation intensity. The graphical and symbolic conceptual models comprehensively describe the entire process and the factors relationships of soil moisture movement in seasonal frozen unsaturated zone. These models are expected to provide scientific basis for practical work in cold areas, such as hydrologic and hydraulic calculation in cold seasons, assessment and utilization of frozen area water resources and agricultural irrigation in cold regions, and also to provide references to the development of mathematical or experimental models in related researching fields.
S. M. Sun et al., "A Conceptual Model of Soil Moisture Movement in Seasonal Frozen Unsaturated Zone", Applied Mechanics and Materials, Vols. 90-93, pp. 2612-2618, 2011