Evaluation of the Algorithms and Parameterizations for Ground Thawing and Freezing Simulation in Permafrost Regions

Ground thawing and freezing depths (GTFDs) strongly influence the hydrology and energy balances of permafrost regions. Current methods to simulate GTFD differ in algorithm type, soil parameterization, representation of latent heat, and unfrozen water content. In this study, five algorithms (one semiempirical, two analytical, and two numerical), three soil thermal conductivity parameterizations, and three unfrozen water parameterizations were evaluated against detailed field measurements at four field sites in Canada’s discontinuous permafrost region. Key findings include: (1) de Vries’ parameterization is recommended to determine the thermal conductivity in permafrost soils; (2) the three unfrozen water parameterization methods exhibited little difference in terms of GTFD simulations, yet the segmented linear function is the simplest to be implemented; (3) the semiempirical algorithm reasonably simulates thawing at permafrost sites and freezing at seasonal frost sites with site-specific calibration. However, large interannual and intersite variations in calibration coefficients limit its applicability for dynamic analysis; (4) when driven by surface forcing, analytical algorithms performed marginally better than the semiempirical algorithm. The inclusion of bottom forcing improved analytical algorithm performance, yet their results were still poor compared with those achieved by numerical algorithms; (5) when supplied with the optimal inputs, soil parameterizations, and model configurations, the numerical algorithm with latent heat treated as an apparent heat capacity achieved the best GTFD simulations among all algorithms at all sites. Replacing the observed bottom temperature with a zero heat flux boundary condition did not significantly reduce simulation accuracy, while assuming a saturated profile caused large errors at several sites

A study of time dependence during serial needle ice events

Soil surface temperature, net radiation and soil heave data during a series of eleven consecutive needle ice growth-melt cycles at Vancouver, Canada, were studied using computer-graphic techniques. A method of analyzing the morphologic evolution of a needle growth using surface temperature and soil heave data is presented. Lastly, an atmospheric-geomorphic correlation matrix derived partially from the analysis of surface temperature-heave data is used to highlight the importance of afternoon evaporation in determining the course of an individual needle ice event within an event series. Bodentemperatur, Strahlungsbilanz und Bodenbewegungsdaten aus Vancouver, Kanada, werden für eine Serie von elf aufeinanderfolgenden Wachstums- und Schmelzzyklen von Eisnadeln graphisch wiedergegeben. Eine Methode zur Analyse der morphologischen Entwicklung des Nadelwachstums mit Hilfe von Bodentemperaturen und Bodenbewegungsdaten wird beschrieben. Schießlich wird eine Korrelationsmatrize zwischen atmosphärischen und geomorphologischen Daten teilweise aus den Daten der Bodentemperatur und Bodenbewegung abgeleitet und dazu benützt, die Bedeutung der Verdunstung am Nachmittag für den Verlauf der Nadelbildung innerhalb der beschriebenen Serie zu demonstrieren.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41660/1/703_2005_Article_BF02250898.pd

Chapter 14 Electrical Properties of Soils

This chapter discusses the electric and electromagnetic methods that are used to evaluate the electrical properties of soils. Electric techniques exploit the flow of a steady-state current in the subsurface, while electromagnetic methods rely on the phenomenon of electromagnetic induction and the wave character of the electromagnetic field. The electrical techniques and associated properties are: (a) spontaneous potential methods in which the formation of water resistivity is determined; (b) resistivity methods in which the apparent resistivity can be calculated using Wenner, Schlumberger, and dipole-dipole arrays; and (c) specific conductivity methods in which the soil-specific conductivity is calculated by incorporating in the analysis of soil geometric factors, such as fabric anisotropy, tortuosity, resistance to solid matrix, bulk fluid phase, and electric double layer. Various parameters that influence the measured electrical properties are also presented, such as the nature of the soil composition (particle size distribution, mineralogy), soil structure (porosity, pore size distribution, connectivity, and anisotropy), moisture content, temperature, concentration of dissolved species in the pore-solution, wet-dry cycles, age of contaminants, and mineral formation due to biodegradation. Finally, the extraction of aquifer hydraulic properties such as porosity and hydraulic conductivity, from the measured electrical properties is discussed

Upward Migration of Soil Moisture by Various Mechanisms upon Freezing

International Conference on Low Temperature Science. I. Conference on Physics of Snow and Ice, II. Conference on Cryobiology. (August, 14-19, 1966, Sapporo, Japan

Thermal soil mechanics

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