Search

Frost heave is major problem for infrastructures build in cold regions. Frost heave occurs due to suction (negative pore water pressure) generated due to the freezing process close to the frost line, i.e., at the frozen fringe. To understand and predict these negative pore water pressures is a key factor to accurately calculate the segregation heave, i.e. heave related to the formation of ice lenses. Segregation heave is the major part of the total heave and also the most challenging to predict. Many attempts have been presented in literature where the generated suction during freezing is related to temperatures, temperature gradients, grain size of the freezing soil etc. Very few laboratory tests have been presented in which the actual suction is measured during the ice lens formation process and compared with theoretical estimations. One reason is that these measurements are challenging. This paper presents results from laboratory measurements of generated suction during freezing. Laboratory tests were conducted on a silty soil sample and suction was measured at the frozen fringe using small pore pressure transducers (PPT’s). The samples were subjected to one-dimensional freezing from top to bottom in an open water system at a constant temperature gradient. Temperatures were measured at various points along the height of the soil sample while suction was measured at middle of the sample. Test results have shown that PPTs do not show pressure change in long-term static pressure test under sub-freezing temperature. For suction measurement at the frozen fringe, pore pressure readings should be measured at various points along the sample height.

Frost heave behavior during soil freezing process is an important issue of concern in cold regions, which is influenced by the hydro-thermal characteristics including the freezing point and water migration. The frost heave is caused by the freeze of water from different sources, i.e. pristine water, migrated water or both; however, it is difficult to identify the contributions of the different water sources to the frost heave, especially for a closed freezing system. Therefore, the calculation method to evaluate the frost heave induced by different water sources still need to be developed. Definitely, freezing experiments under controlled laboratory conditions can help to give a detailed description of the soil freezing process. Therefore, a large-scale one-directional freezing experiment within a closed system was carried out to investigate the hydro-thermal characteristics and frost heave behavior of a saturated silt. The research results showed the effect of the hydro-thermal behavior on the frost heave of the silt within a closed freezing system, and a calculation method was presented to evaluate the frost heaves from pristine water and migrated water, respectively.

Civil engineering buildings are often damaged by frost heave of ground soils in cold regions. The hydro-thermal behavior is a key factor in determining frost heave of soils during freezing process. Moreover, the frost heave is also strongly affected by overburden pressure and external water source. Here, a series of one-directional freezing experiments with a water supply under different applied pressures were carried out to study the effect of hydro-thermal behavior on the frost heave of a saturated silty clay. Four different pressures were applied on the top of each soil sample, respectively, i.e. 50, 150, 300 and 500 kPa. The experimental results indicate that the frost heave of the supplied water is the main component of the total deformation for each soil sample with a water supply. However, the increased applied pressure can restrict water migration, and reduce frost heave during soil freezing process. Furthermore, for the saturated silty clay under different applied pressures, only when the advance rate of the freezing front drops to a critical value, the water intake begins. The start time of the water intake is also delayed with the increased applied pressure. Besides, the shut-off pressure of the saturated silty clay, at which no water flow into or out of the soil sample, is obtained based on the relationship between the critical advance rate of freezing front and the applied pressure.

Snowpack produces a thermal layer that protects soil from freezing and provides a pulse of nutrient-rich water in spring. Climate forecasts for Maine indicate 20–60% reduction in snowfall by 2050. In January 2015, we initiated a snow-removal experiment in Old Town, ME to investigate the impact of snow loss on forest soil conditions. Snow removal significantly lowered winter organic horizon temperatures by 2 °C on average. Soils in snow-removal plots were 25% wetter during the vernal transition because precipitation was not intercepted by snow. These rain-on-soil events caused the formation of concrete frost, delaying soil thaw in snow-removal plots. Our results provide evidence that snowpack loss increases soil frost and can also increase soil moisture, potentially altering biotic function within a coniferous forest type.

Soil frost can have a substantial impact on water flows at the soil surface and—potentially—alter the dynamics of catchment runoff. While these findings are mainly based on studies from alpine and Northern-latitude areas (including permafrost areas), little is known about the significance of soil frost for hydrology in pre-alpine areas, i.e. the region at the transition from central European lowlands to high-alpine areas. Here I synthesize soil temperature data and soil frost observations from ten sites in Switzerland to assess the occurrence of soil frost and to determine its impact on catchment runoff. In addition, a well-established numerical model was used to reconstruct the presence of soil frost in two first-order catchments for single runoff events and winters. The data clearly demonstrates that shallow soil frost has formed regularly in this altitudinal range over the past decade. The presence of a frozen soil surface was found to be highly variable among the sites under study and did not significantly correlate with altitude or forest density. For the first-order catchments, it was not possible to relate important flood peaks or increased runoff coefficients to winter situations with substantial soil frost. Thus, the present analysis suggests that although soil frost is widespread and regularly occurring at this altitudinal range, it has no significant impact on winter runoff in pre-alpine watersheds.

Embankment deformation is a key consideration in high speed railway construction. Frost heave due to temperature and moisture variation is critical to consider in areas of seasonally frozen ground. This paper examined ground temperatures, frost heave, and moisture content in 2013–2014 at two sites along the embankment of the Harbin-Dalian Passenger Dedicated Line (HDPDL) railway. The railway is in seasonally-frozen ground of Jilin Province, China. The embankment at one site (K977) was built on the undisturbed ground surface while the other was in a cut section (K1004). Displacement measurements over one year indicated that frost heave of 14 mm at K977 and 25 mm at K1004 occurred in ballast during the freezing season. During the annual freeze-thaw period, soil moisture content varied drastically in the upper 0.6 m. The frost depth and freezing index were strongly and positively correlated during the freezing season. Soil moisture content was regarded as the primary control on the amount of frost heave, while frost depth was secondary. Furthermore, water vapor diffusion may have been an important contributor to the formation of near-surface ice. At K1004 site, the maximum recorded deformation was large and exceeded the 15 mm Chinese standard for maximum allowable heave. This suggested that high ground water level increased the amount of frost heave.

1 Standing corn residue has been proven to reduce wind erosion in Northeast China, but how standing corn residue affects soils during winter remained unclear. Our objective was to compare soil frost depth associated with two zero-tillage methods [i.e., chopping corn stalks into small sections then spread them on soil (hereafter referred to as ‘CCR’) and standing corn residue (hereafter referred to as ‘SCR’)]. Frost tubes were used to determine soil frost depth, and soil heat flux plates were used to measure soil heat flux 8-cm beneath the soil surface. Compared with CCR treatment, SCR reduced maximum soil frost depth significantly ( p

Introducing ultrasonic radar/sensor into current China Meteorological Agency (CMA)’s frozen soil/frost line observation protocol, a method is proposed to automate soil freeze/thaw state monitoring. Two prototypes were built and tested in both lab condition and onsite experiment. Results suggest that the proposed method exhibits application potential and merits further investment in research. The tested prototypes can capture soil freezing process in one-millimeter accuracy and 10 mins data interval. Comparing to CMA’s best practices with one-centimeter accuracy and one data point per day, the proposed method not only automate the monitoring process but also provides better dataset. Challenges emerged during the onsite experiment and improvements were proposed to address the issues.

From August 2014 to September 2016, the Rosetta spacecraft followed comet 67P/Churyumov-Gerasimenko along its orbit. After the comet passed perihelion, Rosetta performed a flyby manoeuvre over the Imhotep-Khepry transition in April 2016. The OSIRIS/Narrow-Angle-Camera (NAC) acquired 112 observations with mainly three broadband filters (centered at 480, 649, and 743 nm) at a resolution of up to 0.53 m/px and for phase angles between 0.095 degrees and 62 degrees. Aims. We have investigated the morphological and spectrophotometrical properties of this area using the OSIRIS/NAC high-resolution observations. Methods. We assembled the observations into coregistered color cubes. Using a 3D shape model, we produced the illumination conditions and georeference for each observation. We mapped the observations of the transition to investigate its geomorphology. Observations were photometrically corrected using the Lommel-Seeliger disk law. Spectrophotometric analyses were performed on the coregistered color cubes. These data were used to estimate the local phase reddening. Results. The Imhotep-Khepry transition hosts numerous and varied types of terrains and features. We observe an association between a feature's nature, its reflectance, and its spectral slopes. Fine material deposits exhibit an average reflectance and spectral slope, while terrains with diamictons, consolidated material, degraded outcrops, or features such as somber boulders present a lower-than-average reflectance and higher-than-average spectral slope. Bright surfaces present here a spectral behavior consistent with terrains enriched in water-ice. We find a phase-reddening slope of 0.064 +/- 0.001%/100 nm/degrees at 2.7 au outbound, similar to the one obtained at 2.3 au inbound during the February 2015 flyby. Conclusions. Identified as the source region of multiple jets and a host of water-ice material, the Imhotep-Khepry transition appeared in April 2016, close to the frost line, to further harbor several potential locations with exposed water-ice material among its numerous different morphological terrain units.© ESO 2019, OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS-University of Padova, Italy, Laboratoire d'Astrophysique de Marseille, France, Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, Universidad Politechnica de Madrid, Spain, Department of Physics and Astronomy of Uppsala University, Sweden, and Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES, and ASI. The SPICE libraries and PDS resources are developed and maintained by NASA. The authors thank the referee and editors for their questions, remarks, and advices for the improvement of this article.

Frost damage is a powerful agent of geomorphic change. Cracks can grow when the ice pressure in pores reaches a threshold that depends on matrix properties and crack geometry. Mineral surfaces that are preferentially wetted by liquid water rather than ice are coated by premelted liquid at a pressure that is lower than the ice pressure. Because this pressure difference increases as the temperature cools, when the ice pressure is effectively pinned at the cracking threshold, temperature gradients induce gradients in liquid pressure that draw water towards colder temperatures. Porosity increases and frost damage accumulates in regions where water supplies crack growth. To apply this understanding over the large spatial and temporal scales that are relevant to evolving landscapes, we develop a simple model that tracks porosity changes. Our central assumption is that frost damage is correlated with porosity increases under conditions where frost cracking takes place. Accordingly, we account for the permeability reductions with decreased temperature that accompany ice growth along porous pathways and derive general expressions for the porosity change through time at particular depths, as well as the total porosity increase through all depths beneath a point at the ground surface over the time during which cracking occurs each year. To illustrate the resulting patterns of frost weathering, we consider a general case in which the permeability has a power law dependence on temperature and the annual surface-temperature variation is sinusoidal. We find that the degree of frost damage generally decreases with depth, except at localized depths where damage is elevated because the rock spends longer times near the threshold for cracking, leading to enhanced water supply in comparison with neighboring regions. The magnitude of the net expansion that results from porosity changes at all depths beneath the ground surface is increased for seasonal thermal cycles with larger amplitudes, with a broad maximum centered on a mean annual temperature near the threshold required for crack growth. Warmer mean annual temperatures lead to less damage because of the reduction in time during which it is cold enough for cracking, whereas colder mean annual temperatures are accompanied by reduced water supply due to the temperature dependence of permeability. All of the controlling parameters in our model are tied explicitly to physical properties that can in principle be measured independently, which suggests promise for informing geomorphic interpretations of the role of frost weathering in evolving landforms and determining erosion rates.

The impact of snow cover on seasonal ground frost and freeze-thaw processes is not yet fully understood. The authors therefore examined how snow cover affects seasonal ground frost in a coastal setting in northern Sweden. Air and soil temperatures were recorded in a paired-plot experiment, both with and without snow cover, during the frost season 2012–2013. The frequency, duration, and intensity of the freeze-thaw cycles during the frost season were calculated. The results showed that the freeze-thaw frequency was 57% higher at the soil surface and the intensity 10 °C colder in the spring of 2013, when the ground lacked snow cover. Furthermore, the duration of the seasonal freeze-thaw cycle was 30 days longer on average in cases where there was natural snow accumulation. The correlation between air and ground surface temperatures weakened with increased snow-cover depth. The authors conclude that continued increases in air temperature and decreases in snow in coastal northern Sweden might alter fr...

Frosts and extreme minimum temperature events cause significant damage to grapevines. In the Victorian vine growing regions of Australia, these events may cause complete wipe-out of a season's grape production, and millions of dollars of losses. Frost is an important risk to be managed by viticulturalists, and is likely to change under future climatic conditions with impacts on existing wine-grape growing regions. This case-study applies high spatial resolution analysis of minimum night-time temperatures to explore the impact of current and future frost risks. Multivariate Adaptive Regression Splines (MARS) are used to model high-resolution (30 m grid) minimum temperatures for a topographically diverse region in the Yarra Valley wine region in southeastern Australia. Remotely sensed Moderate Resolution Imaging Spectroradiometer (MODIS) night-time temperatures, elevation, terrain indices and meteorological station data were used to develop the model of minimum night-time temperatures. The model is formally validated against independent vineyard minimum temperature records (R2 = 0.68) as well as current distribution of viticulture land-use, which was compared with viticulturists' perceptions of a frost-line in the region. Historical temperature records were then adjusted to produce high-resolution maps of frost occurrence under a hot-dry future climate scenario, and a warm-wet scenario, for the years 2030 and 2050. All the future climate scenarios project down-elevation movement of the frost line of between 10 m and 30 m depending on scenarios. This work has implications for viticulturists who might plan to expand growing areas to lower elevations, or might consider changing to different grape varieties. The method developed here could be applied to other regions or used to explore other future climate scenarios. Keywords: Frost, Elevation, Viticulture, Multivariate Adaptive Regression Splines (MARS), Climate change, Moderate Resolution Imaging Spectroradiometer (MODIS)

The NICE model was extended to include the effect of the micro-topography in slope and shading characteristics and the phase changes in soil moisture on snow/frost depths and snowmelt runoff by combining the land-surface, the multi-layer runoff, and the groundwater flow models (NICE-SNOW). The model was applied to the upstream regions of shrinking Kushiro Mire in the invasion of alder, where the spring runoff affects greatly the annual sediment and nutrient transports because the spring flood continues in longer time than that in typhoon seasons. The simulation reproduced excellently the observed values of annual river discharge including snowmelt runoff with the greater time-to-peak of runoff than in snow-free period, in addition to snow depth, frost depth, soil temperature, soil moisture, and groundwater level, by conducting the quantitative assessment of goodness-of-fit and parameter sensitivity analysis. We quantified that the mechanism of spring snowmelt runoff is related to changes in micro-topography, soil structure, soil temperature, soil moisture, and groundwater flow. The model shows that the local effect of snow depth and the frost depth disappears in the snowmelt runoff discharge of catchment in the same way as some previous researches though they are very important as water resources of catchment. After the frozen soil restricts the infiltration in the coldest part of winter, the thawed soil increases the pore size in the early spring. The NICE-SNOW could explain the snowmelt flood continues a longer time than that in the typhoon period because some part of meltwater flows as an intermediate flow in the partially-thawed hillslope soil layer. This is also related to the simulation result that more than half of total soil moisture stays unfrozen at some places even in winter periods, which indicates that there is a high degree of spatial heterogeneity of frozen ground.

The frost table depth is a critical state variable for hydrological modelling in cold regions as frozen ground controls runoff generation, subsurface water storage and the permafrost regime. Calculation of the frost table depth is typically performed using a modified version of the Stefan equation, which is driven with the ground surface temperature. Ground surface temperatures have usually been estimated as linear functions of air temperature, referred to as ‘n-factors’ in permafrost studies. However, these linear functions perform poorly early in the thaw season and vary widely with slope, aspect and vegetation cover, requiring site-specific calibration. In order to improve estimation of the ground surface temperature and avoid site-specific calibration, an empirical radiative–conductive–convective (RCC) approach is proposed that uses air temperature, net radiation and antecedent frost table position as driving variables. The RCC algorithm was developed from forested and open sites on the eastern slope of the Coastal Mountains in southern Yukon, Canada, and tested at a high-altitude site in the Canadian Rockies, and a peatland in the southern Northwest Territories. The RCC approach performed well in a variety of land types without any local calibration and particularly improved estimation of ground temperature compared with linear functions during the first month of the thaw season, with mean absolute errors

Research on frost heaving of high speed railway subgrade filling in seasonal frozen soil area is developed indoor. Through freezing and thawing strength and frost heaving amount test, the research analyzes factors affecting frost heaving of subgrade filling, points out that water content, fine stuff admixing amount and plasticity of fine-grained soil have relatively large influence on frost heaving, while freezing temperature and freezing and thawing cycle index have relatively small influence. Water content is main factor to have effect on frost heaving of subgrade filling. When the water content reaches to some certain value, even coarse-grained soil can produce considerable frost heaving amount. Therefore, taking effective waterproof and drainage measures is of great importance in subgrade frost heaving prevention and treatment.

A series of freezing experiments were conducted to simulate the frost heave in saturated silt samples with variable thermal boundaries. It is shown that before the frost heave occurs, a small amount of pore water is discharged out of the soil due to the sudden freezing of the super-cooled pore water, and that once the frost heave occurs, the total amount of frost heave is approximately equal to the amount of frost heave due to water intake. A formulation is developed which can be used to determine the initiation time of frost heave. The location of the freezing front and the amount of frost heave are calculated, and the calculated results agree well with the experimental measurements. A criterion for ice lens initiation/growth is presented, according to which an ice lens initiates or grows if the volumetric water content is equal to or greater than 1. It is demonstrated that the predicted ice lenses are similar to the observed ones, showing the validity of the criterion.

a b s t r a c t Soil frost depth in forest ecosystems can be variable and depends largely on early winter air temperatures and the amount and timing of snowfall. A thorough evaluation of ecological responses to seasonally frozen ground is hampered by our inability to adequately characterize the frequency, depth, duration and intensity of soil frost events. We evaluated the use of ground penetrating radar to nondestructively delineate soil frost under field conditions in three forest ecosystems. Soil frost depth was monitored periodically using a 900 MHz antenna in South Burlington, Vermont (SB), Sleepers River Watershed, North Danville, Vermont (SR) and Hubbard Brook Experimental Forest, New Hampshire (HBEF) during winter 2011-2012 on plots with snow and cleared of snow. GPR-based estimates were compared to data from thermistors and frost tubes, which estimate soil frost depth with a color indicating solution. In the absence of snow, frost was initially detected at a depth of 8-10 cm. Dry snow up to 35 cm deep, enhanced near-surface frost detection, raising the minimum frost detection depth to 4-5 cm. The most favorable surface conditions for GPR detection were bare soil or shallow dry snow where frost had penetrated to the minimum detectable depth. Unfavorable conditions included: standing water on frozen soil, wet snow, thawed surface soils and deep snow pack. Both SB and SR were suitable for frost detection most of the winter, while HBEF was not. Tree roots were detected as point reflections and were readily discriminated from continuous frost reflections. The bias of GPR frost depth measurements relative to thermistors was site dependent averaging 0.1 cm at SB and 1.1 cm at SR, and was not significantly different than zero. When separated by snow manipulation treatment at SR, overestimation of soil frost depth (5.5 cm) occurred on plots cleared of snow and underestimation (−1.5 cm) occurred on plots with snow. Despite some limitations posed by site and surface suitability, GPR could be useful for adding a spatial component to pre-installed soil frost monitoring networks. Published by Elsevier B.V.

Frost heave often causes damage to rural water supply pipes in severe cold region, therefore, the anti-frost technology of shallow buried pipe with insulation layer was proposed in this article. Firstly, by analyzing the calculation of frost heave and measuring the ground temperature of the different depth, the optimal buried depth was founded preliminarily. Secondly, establishing the unsteady heat transfer model with the Matlab software, the ground temperature field were simulated when the pipe depth differs. Thus, the conclusion is that the optimal depth is 1.5m for the buried pipes with little atmospheric disturbance effect and the thaw circle is larger

The power, water extraction, and refrigeration (PoWER) system generates electric power, potable water and refrigeration effects simultaneously, and is composed of a micro-turbine and vapor absorption refrigeration system, which typically uses ammonia, heat exchangers, and a turbocharger. In order to improve the efficiency and the electric output power of the micro-turbine portion of the PoWER system, attempts have previously been made to reduce the inlet temperature of the compressor. However, it was problematic to drive it below the freezing point since frost or ice forms from the humidity in re-circulated air. As a result, the ice accretion that attaches on the bell mouth or guide vane might increase the pressure drop, leading to performance loss. Furthermore, large sections that break from the ice accretion may cause damage to the compressor blades. In this paper experiments have been conducted under the same environmental conditions as the PoWER system in order to observe the physical characteristic of the frost formation on cylindrical tubes. The results show the thickness of the frost formation for different air velocities (3, 5, 7 m/s) and surface temperatures (−9.8, −16.6, −24.4°C) with respect to time.

Automated monitoring that combines time-lapse photography and sensor-based data logging can elucidate the environmental conditions, processes and rates of soil movement on remote periglacial hillslopes. This study presents the results from 5 years of time-lapse photography of soil movements, supported by time series data on frost heave, soil temperature, soil moisture and surface weather, on an alpine stone-banked lobe subject to frequent diurnal freeze-thaw cycles and deep seasonal frost on Mt Ainodake in the Japanese Alps. The lobe is dominated by biannual shallow soil movements, mostly originating from diurnal frost heave by needle ice or shallow ice lens formation and approximated by potential frost creep. The surface velocity shows a small interannual variation mainly reflecting snow conditions that control the spatio-temporal variability of freeze-thaw action, while it is independent of mean annual air temperature that influences the intensity of seasonal freezing. Occasional rill erosion occurs when the topmost frozen soil is rapidly thawed and super-saturated by intensive rainfall during seasonal thawing periods. Copyright © 2014 John Wiley & Sons, Ltd.

Freeze-thaw processes in soils, including changes in frost and thaw fronts (FTFs), are important physical processes. The movement of FTFs affects soil hydrothermal characteristics, as well as energy and water exchanges between the land surface and the atmosphere and hydrothermal processes in the land surface. This paper reduces the issue of soil freezing and thawing to a multiple moving-boundary problem and develops a soil water and heat transfer model which considers the effects of FTF on soil hydrothermal processes. A local adaptive variable-grid method is used to discretize the model. Sensitivity tests based on the hierarchical structure of the Community Land Model (CLM) show that multiple FTFs can be continuously tracked, which overcomes the difficulties of isotherms that cannot simultaneously simulate multiple FTFs in the same soil layer. The local adaptive variable-grid method is stable and offers computational efficiency several times greater than the high-resolution case. The simulated FTF depths, soil temperatures, and soil moisture values fit well with the observed data, which further demonstrates the potential application of this simulation to the land-surface process model.

Many infra suructure such as road, railway, building and utility foundations have been damaged by the repeated freezing and thawing of the soil during winter and spring every year in seasonal frost region. The frost penetration depth is most important factor in the design of structure such as road, railway and building in seasonal frost region. This paper presents the results of calculation of frost penetration depth and frost heaving in concrete track for railway construction. Model concrete track were installed near the railway track in Gangwon, Gyeonggi, Choongbuk province and frost penetration depth were measured using methylene blue frost penetration depth gauge. Model concrete track in Cheolwon, frost heaving of concrete track were also evaluated. The measure of maximum frost penetration depth and frost heaving can be applied to design railway track for cold region in Korea.

Frost heaving damage of water conservancy project is widespread. In order to research the failure problems of hydraulic soil slope in dark seasonal frozen soil region, remote monitor and manual observation is carried out combined with field test section layout, which including air temperature, earth temperature, frozen depth, the amount of frost heaving and layered water content. It is researched that the rule of frost heave parameters variation and the damage of soil slope during freeze-thaw cycling. That offers theoretical basis and reference for construction of water conservancy project and guidance for engineering practice.

The Korean Peninsula is considered as a seasonal frozen area that is thawed in the spring and frozen in the winter. The influence of fines of the frost susceptibility of subgrade soils were established by laboratory freezing tests simulating closely the thermal conditions in the field. During the winter season, the climate is heavily influenced by the cold and dry continental high pressure. Because of siberian air mass, the temperature of January is on average. This chilly weather generate the frost heaving by freezing the moisture of soil and damage potential of the geotechnical structure. In the freezing soil, the ice lenses increase the freeze portion of soil by absorbing the ground water with capillary action. However, the capillary characteristics differ from the sort of soil on the state of freezing condition. In this study, ten soil samples are prepared. The basic physical property tests were performed by following the Korean Industrial Standard and the soil specimens were classified by the Unified Soil Classification System (USCS). These classified soils are used to perform the laboratory opened systems freezing test in order to determine the frost heaving characteristics of soils such as unfrozen water content, heaving amount, and freezing depth.

One of the most important factors affecting pavement performance is climate, including frost action and precipitation. The performance of pavements in frost-affected regions depends to a large degree on the depth of frost penetration. In this paper, a simple predictive tool is developed to calculate a new correction coefficient depending upon the thermal ratio and fusion parameter. The new correction coefficient can be used in follow-up calculations to estimate the depth of frost penetration for both uniform and layered soils in frost-affected regions to evaluate the performance of pavement. The results of the proposed method are found to be in excellent agreement with reported data in the literature with average absolute deviation being less than 0.8%. The predictive tool is simple, straightforward and can be readily implemented in any standard spreadsheet programme leading to accurate, smooth and non-oscillatory data points. The prime application of the method is as a quick-and-easy evaluation tool in c...

PURPOSES: This study is to evaluate a ground water level effect on frost heaving in road pavements. METHODS: The effects of water table on frost heaving in pavement systems were evaluated from the mechanical analysis using FROST program. The input parameters and boundary conditions were determined by considering climates, pavement sections, and material properties specially subgrade soil types in Korea. RESULTS: When the water table located above the freezing depth, amount of frost heaving caused by freezing the water in pavement itself was big enough to damage in pavement system, although pavement system consists of fully non-frost-susceptible materials with sufficient thickness of anti-freezing layer. The amount of frost heaving was decreased rapidly with increasing the distance between the water table and freezing depth. CONCLUSIONS: It was concluded that there is no engineering problems related with frost heaving in practical sense when the distance between freezing depth and water table is over 1.5m for having subgrade soils less than 50% of #200 sieve passing to meet specification on quality control in Korea.

Frost heave, which is the volumetric expansion of frozen soil, has great ecological significance, since it creates water storage spaces in soils at the beginning of the growing season in cold temperate forests. To understand the characteristics of frost heave in seasonally frozen soil and the factors that impact its extent, we investigated the frost heave rates of forest soil from different depths and with different soil moisture contents, using both lab-based simulation and in situ measurementin a broadleaved Korean pine forest in the Changbai Mountains (northeastern China). We found that frost heave was mainly affected by soil moisture content, soil type, and gravitational pressure. Frost heave rate increased linearly with soil moisture content, andfor each 100% increase in soil moisture content, the frost heave rate increased by 41.6% (loam, upper layer), 17.2% (albic soil, middle layer), and 4.6% (loess, lower layer). Under the same soil moisture content,the frost heave rate of loam was highest, whereas that of loess was lowest, and the frost heave of the uppermost 15 cm, which is the biologicallyenrichedlayer, accounted for ~55% of the frost heave. As a result, we determined the empirical relationship between frost heave and freezing depth, which is important for interpreting the effects of frost heave on increases in the storage space of forest soils and for calculating changes in soil porosity.

The response of seasonal soil freeze depth to climate change has repercussions for the surface energy and water balance, ecosystems, the carbon cycle, and soil nutrient exchange. Despite its importance, the response of soil freeze depth to climate change is largely unknown. This study employs the Stefan solution and observations from 845 meteorological stations to investigate the response of variations in soil freeze depth to climate change across China. Observations include daily air temperatures, daily soil temperatures at various depths, mean monthly gridded air temperatures, and the normalized difference vegetation index. Results show that soil freeze depth decreased significantly at a rate of −0.18 ± 0.03 cm yr−1, resulting in a net decrease of 8.05 ± 1.5 cm over 1967–2012 across China. On the regional scale, soil freeze depth decreases varied between 0.0 and 0.4 cm yr−1 in most parts of China during 1950–2009. By investigating potential climatic and environmental driving factors of soil freeze depth variability, we find that mean annual air temperature and ground surface temperature, air thawing index, ground surface thawing index, and vegetation growth are all negatively associated with soil freeze depth. Changes in snow depth are not correlated with soil freeze depth. Air and ground surface freezing indices are positively correlated with soil freeze depth. Comparing these potential driving factors of soil freeze depth, we find that freezing index and vegetation growth are more strongly correlated with soil freeze depth, while snow depth is not significant. We conclude that air temperature increases are responsible for the decrease in seasonal freeze depth. These results are important for understanding the soil freeze–thaw dynamics and the impacts of soil freeze depth on ecosystem and hydrological process.

Monitoring near-surface soil freeze/thaw patterns is becoming essential under the context of global changes as it is more sensitive to climatic fluctuation compared with subsurface thermal characteristics and its evolution could be an early warning of changes in near-surface permafrost. It requires continuous long term and stable data record for understanding hydrological, ecological and biogeochemical responses of permafrost to global climate change. AMSR2 (Advanced Microwave Scanning Radiometer 2) is designed as a successor of AMSR-E (Advanced Microwave Scanning Radiometer – Earth Observing System) to ensure continuity of such observation. In this study, a linear regression is used to inter-calibrate the AMSR-E and AMSR2 brightness temperatures. Then discriminant function algorithm is adopted to produce a long term freeze/thaw data record. It is compared with in situ air temperature measurements from both the temporal and spatial aspects. The results show that the accuracy is consistent between AMSR-E and AMSR2 with a value above 85 %, according to the result of spatial distribution accuracy. Analysis is conducted with this data record to explore the spatial distribution of frost days, its changing trend and the frost probability of each pixel on a specific date. The mean annual frost days of high northern latitude (HNL, > 45° N) zone is 214.2 ± 69.5 days and the trend of frost days indicates that the frost period is decreasing at a rate of −0.0065 day/month in 27 % of the domain which is defined by significance level of the F-test, and most of which are concentrated in the high latitude area specifically over the Northeast of Canada, Central and Eastern Russia and most part of Eastern Europe. The significant changes in frost days mostly occur in regions of discontinuous permafrost and transient permafrost. The spatial distribution of the frost days and its trend variations are found to be consistent with the minimum temperature anomalies trend. It indicates that the global warming is not constant at different regions over the globe. Further analysis over the Qinghai-Tibetan Plateau where discontinuous permafrost, island permafrost, seasonally frozen ground exist demonstrated that the frost period is shortening slightly over the past decade, and the last frost date is advanced over more than half of the region. It is considered to be a remarkable indication for permafrost degradation in this area.

Frost tubes filled with methylene blue solution are commonly used tools for measuring soil frost and thaw depths in the field. To quantify the accuracy of this method, soil frost depths were measured in agricultural fields in the Tokachi district of the northernmost of Japan's main islands. The frost depths measured using frost tubes coincided with those determined from direct observations of the soil profile. The root mean square error (RMSE) between these two methods (i.e. frost tubes and direct observations) was ± 0.035 m, which is expected for frost tubes in this region. The soil temperature profile was characterized over four winters using thermocouples to estimate soil frost depths in an experimental field in central Tokachi. Frost depths were also measured using frost tubes during this period. A scatter diagram of the frost depths obtained using these two methods showed a concentration of points along a 1:1 line. The RMSE between these two methods was ± 0.028 m, suggesting that frost depth can be accurately estimated from the soil temperature profile. Unlike soil frost depth, soil thaw depths measured using frost tubes were consistently deeper than those determined through direct observation of the profile of soil hardness. This might be true because the frozen soil around the frost tube thawed earlier because of the greater insolation and heat conduction from atmosphere resulting from the decrease in snow cover as a result of snowmelt around the frost tube. However, because a scatter diagram of the thaw depths obtained using these two methods showed an approximately linear relation, the thaw depths measured using frost tubes can be calibrated using this relation.

A new instrument for freezing-thawing test was developed by Cold and Arid Regions Environmental and engineering research institute (CAREERI), Chinese academy of sciences. By using this device, silty clay of different water content and dry density were frozen under different conditions of temperature gradients in seasonally frost soil regions, By doing so,the regularity of frost heave amount, water content and dry density in seasonally frost soil regions were illuminated. The test results show that the final frost heave amount enhances with the increase of the water content and dry density. The results may provide some technical and theoretical references for the application of artificial ground freezing in the seasonally frost soilregions.

In this study, a simple model that describes frost formation over ground aircraft surfaces is presented. The model uses the data of the aircraft surface temperature, air temperature and air velocity to predict the frost thickness. The frost surface temperature and the frost thickness under different atmospheric conditions are investigated. The results indicate the frost thickness increases with the air velocity and the air temperature, decrease with the surface temperature. This model enables forecast of the frost formation over ground aircraft surface.

In the northernmost region of Japan (Hokkaido Island), earlier onsets of thick snowcover in recent years (post 1980) have reduced the penetration depth of soil frost, resulting in over-winter survival of unharvested small potato (Solanum tuberosum) tubers that emerge as weeds in the spring in rotation crop fields. To prevent the occurrence of potato weeds, a method was developed to manipulate soil-frost depths by artificially controlling snowcover thickness, guided by a simple numerical model that simulates soil freezing-thawing processes using daily mean air temperature and snowcover thinckness as input variables. The method involves removal of snowcover to expose the soil surface in the beginning of winter until the soil freezes to a sufficient depth. After that time, snow is deposited back or allowed to accumulate naturally to prevent further penetration of frost, which may cause undesirable delay in the seeding of spring crops. Field trials indicated that the model predicted frost depths within several centimeters of observed values, when measured temperature and snowcover thickness were used as model input. Based on the field and laboratory data, a soil temperature of −3°C is necessary for complete elimination of potato tubers. To achieve this temperature in potato-burial zones without causing excessive freezing, an optimal frost depth is 0.3 to 0.4 m. The method is being adopted by progressive potato producers in the region, who use tractor-mounted snow ploughs to manipulate snowcover over a large scale. This is an emerging new technology for agricultural adaptation to climate variability.

The 813-mm-diameter China–Russia Crude Oil Pipeline enters northeastern China at Lianyin, Mo'he County, Heilongjiang Province and crosses 441 km of warm discontinuous, sporadic and isolated patches of permafrost and 512 km of seasonally frozen ground before reaching Daqing, China. It is inevitable that the buried pipeline is subject to frost heave and/or thaw settlement when it passes through regions of permafrost and seasonally frozen ground with available moisture. Therefore, stress and deformation analyses of the pipe subject to frost action or thaw settlement are important for the safety, long-term stability and economic feasibility of the buried oil pipeline system. Based on the (empirical) frost heave and/or thaw settlement coefficients, a simple thermal elasto-plastic finite element computation model is put forward for analyzing the stress and strain state of the pipe. The influences of soil temperatures on the soil deformation were considered, but those of the soil deformation on the soil temperatures were ignored in the modelling. Finally, two examples of the application of the computation model are presented, in which the stress and deformation of a pipe exposed to frost heave or thaw settlement is calculated. The results of the frost action computation show that the effective stress on the pipe increases linearly with the frost heave deformation. The largest pipe deformations and stresses may occur when crossing frost mounds due to differential frost heaving. The stress and deformation smooth out from the frost mound. The results of thaw settlement computation show that the pipe stress changes greatly near the interface of thaw settlement zone and no thaw settlement zone, and the thaw settlement has small effect on the stability of oil-pipeline. The computation results show that the oil pipeline design in the permafrost regions should pay more attention on frost heave hazard than thaw settlement hazard.

An experimental study concerning frost formation on a cold flat surface in atmospheric air flow subjected to the effect of 20 kHz ultrasound was conducted. A close observation of the frost nucleation and frost growth processes with and without the effect of 20 kHz ultrasound was made with a microscopic image system. The size and distribution of freezing water droplets during the initial nucleation period were described and the frost layer structure and thickness variation with time were presented. It was found that the freezing water droplets formed on the surface with the effect of ultrasound are smaller and sparser compared with those without the effect of ultrasound. The coverage of freezing droplets is all less than 52% with the effect of ultrasound compared with that all more than 65% without ultrasound under some tested conditions. Furthermore, the frost layer structure with a special pattern like “frost line” is observed on the cold surface and very small growth of the frost layer can be seen with the effect of ultrasound. The rate of frost layer thickness reduction with the effect of ultrasound compared with that without ultrasound is about 75%. The experimental results also showed that the frost formation process on the flat surface is remarkably restrained due to the effect of ultrasound.

The dynamics of stone-banked lobes were investigated by monitoring soil movements and environmental parameters over 14 years on a limestone slope subject to deep seasonal frost. The monitored parameters included downslope soil movement, frost heave, soil temperature, moisture and snow depth. Despite being composed of the same soil, lobes on the upper slope (∼20°) display pressure ridges on the tread and terminate in a high riser (∼1 m), whereas lobes on the lower slope (∼10°) have a flat tread and a low riser (∼0.5 m). The long-term monitoring demonstrates that gelifluction, resulting from seasonal frost heave of approximately 5 cm and thaw settlement, occurs annually in the lower lobes at a mean surface rate of 4 cm a−1 and with a movement base at approximately 40-cm depth. The rate of gelifluction shows some interannual fluctuation depending primarily on the annual frost heave amount, but overall regularity of the rate and depth of movement regardless of seasonal frost depth results in lobes having similar morphologies. On the upper, steeper lobes located just below late-lying snow patches, rapid, shallow mudflows (∼20 cm thick) are often superimposed on gelifluction. The rate of surface movement varies spatially, in places exceeding 2 m per event. The prolonged water supply and low consistency limits of the limestone soil favour mudflows on seasonal thawing. The transported sediments pile up near the lobe front, resulting in a high riser. Such modification of solifluction lobes by mudflows can occur in other slopes with similar gradients, soils, frost and snow conditions. Copyright © 2010 John Wiley & Sons, Ltd.

Through changing soil thermal regimes, soil moisture and affecting weathering and erosion processes plants can have an important effect on the physical properties and structure of soils. Such physi...

This paper reports on mapping of water frost and ice on Mars, in the range of latitudes between 30°S and 30°N. The study has been carried out by analysing 2485 orbits acquired during almost one martian year by the Mars Express/OMEGA imaging spectrometer. Water frost/ice is identified by the presence of ∼1.5 μm, ∼2 μm and ∼3.0 μm absorptions. Although the orbits analysed in this study cover all seasons, water frost/ice is observed only near the aphelion seasons, at Ls = 19° and at Ls = 98–150°. Water frost/ice is detected mainly on the southern hemisphere between 15°S and 30°S latitude while it has not been identified within 15°S–15°N. In the northern hemisphere, the water frost/ice detection is complicated by the presence of clouds. Usually, water frost/ice is found in shadowed areas, while in few cases it is exposed to the sunlight. This indicates a clear relationship with the local illumination conditions on the slopes which favour the water frost/ice deposition on the surface when the temperatures are very low. OMEGA observations span from 10 to 17 LT and the frost/ice is detected mainly between 15 and 16 LT, with practically no detection before 13 LT. We think this is due to the fact that the 10–12 LT observations occur at large distances and it is not a local time effect. A thermal model is used to determine the deposition conditions on the sloped surfaces where water frost/ice has been found. There, daily atmospheric saturation does not occur on pole facing 10–25° slopes with current water vapour abundances but only by assuming values greater than 40 pr μm. Moreover, the water frost/ice is not detected during the northern winter, even if the thermal model foresees daily saturation on 25° slopes.

Climatic factors are divided into more equable and more variable. More variable factors include a multi-year weather regime of a particular region or country. Climatic information, based on which climatic parameters and various quantitative indicators are calculated, is obtained from diferent sources. Primary meteorological information is the data obtained during the observations in meteorological stations. Another meteorological information especially important for road design, construction, and maintenance is obtained from the Road Weather Information System (RWIS). Lithuania belongs to a number of countries experiencing a large effect of climatic conditions on road design, construction, and repair. Climatic conditions are the amplitude and speed of temperature variation, temperature max and min, precipitation, wind direction and speed, thickness of snow cover, and depth of such ground. One of the most important climatic factors in winter is a frozen ground. The depth of such ground depends on a negative temperature and its stability, thickness of snow cover, and the start of its formation, vegetation, soil properties, and composition. The action of frost changes the structure of soil and affects the surface and underground water interchange. Therefore, investigations and analysis of the change in the depth of frozen ground is important from both the theoretical and practical point of view.

The seasonal change in depths of the frozen and thawed soils within their active layer is reduced to a moving boundary problem, which describes the dynamics of the total ice content using an independent mass balance equation and treats the soil frost/thaw depths as moving (sharp) interfaces governed by some Stefan-type moving boundary conditions, and hence simultaneously describes the liquid water and solid ice states as well as the positions of the frost/thaw depths in soil. An adaptive mesh method for the moving boundary problem is adopted to solve the relevant equations and to determine frost/thaw depths, water content and temperature distribution. A series of sensitivity experiments by the numerical model under the periodic sinusoidal upper boundary condition for temperature are conducted to validate the model, and to investigate the effects of the model soil thickness, ground surface temperature, annual amplitude of ground surface temperature and thermal conductivity on frost/thaw depths and soil temperature. The simulated frost/thaw depths by the model with a periodical change of the upper boundary condition have the same period as that of the upper boundary condition, which shows that it can simulate the frost/thaw depths reasonably for a periodical forcing.

Rates and processes of frost weathering in the Alps were investigated by visual observations of intensively shattered rocks, continuous monitoring of frost wedging and rock temperatures in bedrock and measurements of rockfall activity. Rapid frost weathering of hard-intact rocks occurs along lakes and streams where seasonal freezing promotes ice segregation in the rock. Otherwise, rocks require pre-existing weakness or a long exposure period for intensively shattered. Automated monitoring shows that crack opening occurs at three scales, including small opening accompanying short-term frost cycles, slightly larger movements during seasonal freezing and occasional large opening originating from refreezing of snow-melt water during seasonal thawing. The opening events require at least partial water saturation in the crack. The repetition of crack opening (frost wedging) results in permanent opening and finally debris dislocation. Debris collections below fractured rockwalls show that pebble falls occur at an average rate of about 0.1 mm a − 1 with significant spatial and inter-annual variations. Occasional large boulder falls significantly raise the rockwall erosion rates, controlled by such factors as the joint distribution in the bedrock, repetition of annual freeze–thaw cycles and extraordinary summer thaw.