A hydraulic conductivity model of frozen soils with the consideration of water films

2021 ◽  
Author(s):  
Feng Ming ◽  
Wansheng Pei ◽  
Mingyi Zhang ◽  
Lei Chen
Keyword(s):  
Hydraulic Conductivity ◽  
Frozen Soils ◽  
Conductivity Model ◽  
Water Films

An unsaturated hydraulic conductivity model for compacted GMZ01 bentonite with consideration of temperature

2013 ◽  
Vol 71 (4) ◽  
pp. 1937-1944 ◽  
Author(s):  
W. M. Ye ◽  
M. Wan ◽  
B. Chen ◽  
Y. G. Chen ◽  
Y. J. Cui ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Conductivity Model ◽  
Gmz01 Bentonite ◽  
Unsaturated Hydraulic Conductivity

scholarly journals A parameterization of respiration in frozen soils based on substrate availability

2015 ◽  
Vol 12 (14) ◽  
pp. 12027-12059 ◽  
Author(s):  
K. Schaefer ◽  
E. Jafarov
Keyword(s):  
Time Scales ◽  
Substrate Availability ◽  
Scaling Factors ◽  
Frozen Soils ◽  
Water Fraction ◽  
Water Films ◽  
Incubation Experiments ◽  
Substrate Diffusion ◽  
Permafrost Regions ◽  
Continuous Loss

Abstract. Respiration in frozen soils is limited to thawed substrate within the thin water films surrounding soil particles. As temperatures decrease and the films become thinner, the available substrate also decreases, with respiration effectively ceasing at −8 °C. Traditional exponential scaling factors to model this effect do not account for substrate availability and do not work at the century to millennial time scales required to model the fate of the nearly 1700 Gt of carbon in permafrost regions. The exponential scaling factor produces a false, continuous loss of simulated permafrost carbon in the 20th century and biases in estimates of potential emissions as permafrost thaws in the future. Here we describe a new frozen biogeochemistry parameterization that separates the simulated carbon into frozen and thawed pools to represent the effects of substrate availability. We parameterized the liquid water fraction as a function of temperature based on observations and use this to transfer carbon between frozen pools and thawed carbon in the thin water films. The simulated volumetric water content (VWC) as a function of temperature is consistent with observed values and the simulated respiration fluxes as a function of temperature are consistent with results from incubation experiments. The amount of organic matter was the single largest influence on simulated VWC and respiration fluxes. Future versions of the parameterization should account for additional, non-linear effects of substrate diffusion in thin water films on simulated respiration. Controlling respiration in frozen soils based on substrate availability allows us to maintain a realistic permafrost carbon pool by eliminating the continuous loss caused by the original exponential scaling factors. The frozen biogeochemistry parameterization is a useful way to represent the effects of substrate availability on soil respiration in model applications that focus on century to millennial time scales in permafrost regions.

On the prediction of hydraulic conductivity of frozen soils

1996 ◽  
Vol 33 (1) ◽  
pp. 176-180 ◽  
Author(s):  
Vlodek R Tarnawski ◽  
Bernhard Wagner
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Bulk Density ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Input Data ◽  
Unfrozen Water ◽  
Frozen Soils ◽  
Unfrozen Water Content

This paper describes a mathematical model for predicting the hydraulic conductivity of partially frozen soils on the basis of limited input data such as grain size distribution and bulk density or porosity. A new model is based on an analogy for the hydraulic conductivity of frozen and unfrozen soils and models for the estimation of hydraulic properties of soils and unfrozen water content. Campbell's model was used for prediction of soil-water characteristics from limited data, while unfrozen water content was obtained from two models (by P.J. Williams and D.M. Anderson) applied to two different temperature ranges. The new model can be used for the rapid estimation of the hydraulic conductivity of practically any freezing soil having log-normal grain size distribution and for computer simulation of moisture migration in soils below the freezing point. An acceptable conformity between the model prediction and measured data for pure sand has been achieved. The computer program developed requires the following input data: grain size distribution, bulk density or porosity, and soil temperature. Key words: frozen soils, hydraulic conductivity, bulk density, grain size distribution, unfrozen water content.

Hydraulic conductivity in frozen soils

1976 ◽  
Vol 1 (4) ◽  
pp. 349-360 ◽  
Author(s):  
T. P. Burt ◽  
P. J. Williams
Keyword(s):  
Hydraulic Conductivity ◽  
Frozen Soils

Using soil freezing characteristic curve to estimate the hydraulic conductivity function of partially frozen soils

2012 ◽  
Vol 83-84 ◽  
pp. 103-109 ◽  
Author(s):  
Tezera F. Azmatch ◽  
David C. Sego ◽  
Lukas U. Arenson ◽  
Kevin W. Biggar
Keyword(s):  
Hydraulic Conductivity ◽  
Characteristic Curve ◽  
Soil Freezing ◽  
Frozen Soils ◽  
Conductivity Function

Hydraulic Conductivity Measurement for Three Frozen and Unfrozen Soils in the Red River of the North Basin

2021 ◽  
Vol 64 (3) ◽  
pp. 761-770
Author(s):  
Debjit Roy ◽  
Xinhua Jia ◽  
Xuefeng Chu ◽  
Jennifer M. Jacobs
Keyword(s):  
Hydraulic Conductivity ◽  
Sandy Loam ◽  
Field Capacity ◽  
Frozen Soil ◽  
Red River ◽  
Silty Clay ◽  
Frozen Soils ◽  
Soil Hydraulic Conductivity ◽  
The North ◽  
Soil Hydraulic

HighlightsHydraulic conductivity was measured in frozen and unfrozen soil conditions by a minidisk infiltrometer.In the RRB, frozen sandy loam and silty clay soils had the highest and lowest hydraulic conductivity, respectively.Three simple equations were developed for the three soils to predict frozen soil hydraulic conductivity.Freeze-thaw cycles reduced soil hydraulic conductivity.Abstract. Hydraulic conductivity (k) is a key parameter in describing water movement through a soil profile. In the Red River of the North basin (RRB), the hydraulic properties of frozen soils vary with temperature, water content, and other factors. In this study, a minidisk infiltrometer was used to measure the k values of three soils from the RRB: Colvin silty clay loam, Fargo silty clay, and Hecla sandy loam. The k values were measured for frozen and unfrozen soils with five different initial soil water contents: oven dry, permanent wilting point, field capacity, midway between permanent wilting point and field capacity, and saturation. The results showed that the mean k value of a frozen soil increased with an increase in initial soil water contents. Hecla soil had the highest k values and Fargo soil had the lowest k values for frozen soils. Three equations were fitted with the measured k values of Colvin silty clay loam, Fargo silty clay, and Hecla sandy loam soils. The k values were also estimated using the Motovilov model. When evaluating model performance, the fitted regression models agreed more closely with the measured k values (index of agreement, d, values of 0.96, 0.94, and 0.94 for Colvin, Fargo, and Hecla soils, respectively) than Motovilov models. Based on overall considerations of statistical measures, the fitted regression models predicted the k values better than Motovilov models for all three frozen soils. It was also found that the k values decreased with an increase in the number of the freeze and thaw cycles that changed the soil properties. Keywords: Frozen soil, Hydraulic conductivity, Mini disk infiltrometer, Red River Valley.

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