Effect of Temperature on Frost-Free Days and Length of Crop Growing Season across Southern Ontario

Climate change has an impact on various climatic variables. In this study our focus is mainly on temperature characteristics of climate parameter. In temperate and humid regions like southern Ontario, the effect of climate change on Frost-free days in winter is distinctive. The average annual temperature is going upward but the extreme increase is in the winter temperature. Winter average temperature is going up by about 2˚C. However, extreme daily minimum temperature is going up by more than 3˚C. This climate effect has a great impact on the nature of precipitation and length of frost-free days. The snowfall over winter months is decreasing and the rainfall is increasing. However, the number of frost-free days during late fall months, early winter months, late winter months and early spring months are increasing. This result reveals an increase in length of the growing season. This research focuses on the effect of change in climatic variables on Frost-free days in Southern Ontario. Therefore, special attention should be given to the effect of change in climate Frost-free conditions on length of crop growing in winter season for potential investigation.

Assessment of the spatial extent of permafrost in the Upper Indus Basin(UIB)

Climate change differentially influences the frozen ground,a major dynamic component of the cryosphere,on a local and regional scale.Under the warming climate with pronounced effects reported at higher altitudes,the characterization of the frozen ground is very important in the Upper Indus Basin(UIB),an important and critical region with respect to climate and hydro-glaciological dynamics.In this study,the efficiency and reliability of the surface frost number model are assessed in delineating the spatial extent of different classes of frozen ground in the region.The daily MODIS land surface temperature(LST)with ground surface temperature(GST)and surface geomorphological expressions as ground validation datasets are used jointly in efficiently determining the extent of different classes of frozen ground(continuous and discontinuous permafrost and seasonal frost).The LST and GST resonate with each other in the annual cycle of temperature variation,however,with mean annual LST exhibiting an offset(cold bias)of 5 to 7℃relative to mean GST.This study shows that the highest permafrost extent is observed in areas where the lowest thinning rates of glacier ice are reported and vice versa.The surface frost number model categorizes an area of 38%±3%and 15%±3%in the UIB as permafrost and seasonal frost,respectively.Based on the altitude model,the lower limit of alpine permafrost is approximated at a mean altitude of 4919±590 m a.s.l.in the UIB.The present study acts as preliminary work in the data sparse and inaccessible regions of the UIB in characterizing the frozen and unfrozen ground and may act as a promising input data source in glaciohydro-meteorological models for the Himalaya and Karakoram.In addition,the study also underlines the consideration of this derelict cryospheric climatic variable in defining and accounting for the sustainable development of socio-economic systems through its intricate ramification on agricultural activity,landscape stability and infrastructure.

Dynamic response characteristics of a circular lined tunnel under anisotropy frost heave of overlying soil at the tunnel portal section in cold regions

The rapid development of traffic engineering in cold regions and its consequent problems need to be considered.In this paper,the dynamic response characteristics of the tunnel portal section in cold regions with harmonic load acting on the lining were studied in the frequency domain.The lining is in close contact with the frozen soil,and there is relative movement between the frozen and unfrozen soil due to the phase change.The analytical solution of the vibration of tunnel portal section caused by the harmonic load acting on the lining was derived under the consideration of the anisotropy frost heave of overlying soil.Based on the continuity conditions and boundary conditions,the undetermined coefficients were obtained,and the analytical solutions for different medium displacements and stresses of the cold-region tunnel system were acquired.The vertical pressure coefficient was equivalently simplified as a variable that could be used to replace the thickness of the overlying soil above the tunnel.The analysis of the parameter model shows that the change of the medium parameters(lining,frozen,and unfrozen soil)affects the circumferential stresses,the radial displacements and their peak frequencies of the soil.For example,the increase of density ratio of tunnel lining to frozen soil decreases the radial stresses of the frozen and unfrozen soil;the increase of volumetric frost heaving strain of the frozen soil increases the radial displacements of the frozen surface and decreases the stability of the frozen surface;the increasing of thickness of the frozen soil significantly reduces the radial displacement of unfrozen soil at dimensionless radius η=4.5 compared with that of frozen soil at η=1.5.

Influence of thermal insulation layer schemes on the frost heaving force in tunnels

In extreme cold regions,a thermal insulation layer(TIL)is commonly employed to mitigate the detrimental effects of frost heaving forces in tunnels.Optimizing the laying scheme of TIL,specifically minimizing frost heaving forces,holds considerable importance in the prevention of frost damage.This research developed a two-dimensional unsteady temperature field of circular tunnels by using the difference method(taking the off-wall laying method as an example)based on the law of conservation of energy.Then,the frozen circle and water migration coefficient were introduced to establish the relationship between the temperature field and frost heaving forces,and a reliable methodology for calculating these forces under the specific conditions of TIL installation was developed.Then(i)the influence of the air layer thickness of the off-wall laying method,(ii)different laying methods of TIL,(iii)the TIL thickness,(iv)the thermal conductivity of the TIL,and(v)the freeze-thaw cycles on the frost heaving force were investigated.The results showed that the frost heaving force served as a reliable and effective metric for evaluating the insulation effect in tunnels.In order to avoid frost damage in compliance with the design requirements,the insulation effects from various laying methods were established,in descending efficacy order as follows:off-wall laying,double layer laying,surface laying,and sandwich laying.Our findings revealed that the optimal thickness for the air layer in the offwall laying method was 0.10 m.The insulation effect of materials with a thermal conductivity below 0.047 W/(m·℃)was furthermore found to be good.Under freeze-thaw cycle conditions,it is concluded that to prevent frost damage,the TIL thickness should be the sum of the thickness r1 of the first freeze-thaw cycle without frost heaving forces and an additional reserve value 0.06r1 of the TIL thickness.

Deformation monitoring and analysis at two frost mounds during freeze–thaw cycles along the Qinghai–Tibet Engineering Corridor

This paper presents various deformation-monitoring technologies employed to monitor the frost heave and thaw settlement of two mounds along the Qinghai–Tibet Engineering Corridor(QTEC), China. The QTEC is known as a critical infrastructure and passage connecting inland China and the Qinghai–Tibet Plateau(QTP). Three technologies—global navigation satellite system(GNSS), terrestrial laser scanning(TLS), and unmanned aerial vehicle(UAV)—were used to estimate the freeze/thaw–induced 3D surface deformation of two frost mounds. Our results showed that (1) the two frost mounds exhibited mainly thaw settlement in thawing periods and frost heave in the freezing period, but frost heave dominated after repeated freeze–thaw cycles;(2) different zones of the mounds showed different deformation characteristics;(3) active-layer thickness(ALT) and elevation changes were highly correlated during thaw periods;(4) integrated 3D-measurement technologies can achieve a better understanding and assessment of hazards in the permafrost area.

Analysis on the Climate Variation Characteristics of Frost in Shandong Province

[Objective] The research aimed to study the climate variation characteristics of frost in Shandong Province. [Method] The daily minimum surface temperature ≤ 0 ℃ in autumn or spring was as the frost index. Based on the daily minimum surface temperature data in 67 meteorological observatories of Shandong Province during 1961-2008, the variation characteristics of first, last frost dates and frost-free period in Shandong Province were analyzed by using the climate diagnosis analysis method. [Result] The climate characteristics of first, last frost dates and frost-free period had the obvious geographical differences in Shandong Province in recent 48 years. The extreme differences of first, last frost dates and frost-free period were all above the three times of their standard deviations. It illustrated that the dispersion degrees of first, last dates and frost-free period were all very big. The average first frost date postponed with 1.99 d/10 a velocity in Shandong Province in recent 48 years, and the last frost date advanced with 1.46 d/10 a velocity. The postponing range of first frost date was bigger than the advancing range of last frost date, and the frost-free period prolonged with 3.42 d/10 a velocity. Seen from the interdecadal variations, the first frost date started to obviously postpone, and the last frost date obviously advanced since the 1990s. The frost-free period also started to obviously prolong since the 1990s. [Conclusion] The research provided the certain reference for the predication, prevention of frost disaster and the structure adjustment of crops.

The effect of confining boundary on soil deformation in one dimensional frost heave tests and the theoretical volume correction

Frost heave is one of the major complications in highway construction in cold regions. Laboratory experiments are im- portant in the study frost heave behavior of soils, and one-dimensional frost heave experiments are the easiest way to evaluate the soil frost heave potential. In a one dimensional frost heave test, the deformation in axial direction is non-uniform because of the confining effect of the cutting ring＇s sidewall. If the effect of confining boundary on soil de- formation is ignored, the deformation will be over-estimated. In this paper, the effect of confining boundary on soil de- formation is theoretically studied and a volume correction method is developed and applied to the frost heave test of a sulfite saline soil. Test results demonstrate that the sulfite saline soil will expand to a loose, low-density state after several freezing-thawing cycles under the condition of zero axial stress.

Centrifuge model test on performance of thermosyphon cooled sandbags stabilizing warm oil pipeline buried in permafrost

The thaw settlement of pipeline foundation soils in response to the operation of the first China-Russia Crude Oil Pipeline along the eastern flank of the northern Da Xing'anling Mountains in Northeast China was simulated in a physical model test(with a similitude ratio of 1/73) in a geotechnical centrifuge. Two pipes of a supported and an unsupported section were evaluated over a testing period for simulating 20 years of actual pipeline operation with seasonal cyclically changing oil and ambient temperatures. The results show that pipe settlement of the supported pipe was 45% of settlement of the unsupported pipe. Settlement for the unsupported section was approximately 35% of the thaw bulb depth below the initial pipe elevation, only 30% of that for the supported pipe due to the influence of the supports. The final thaw bulbs extended approximately 3.6 and 1.6 times of the pipe diameter below the unsupported and supported pipe bottom elevations, respectively. The sandbag supports kept frozen during the test period because of cooling effect of the thermosyphons. The maximum bending stress induced over the 20 m span length from bearing of the full cover over the pipe would be equivalent to40% specified minimum yield strength(SMYS). Potential buckling of the pipe should be considered as the ground thaws.This study also offers important data for calibration and validation of numerical simulation models.

Coupled thermo-hydro-mechanical modeling of frost heave and water migration during artificial freezing of soils for mineshaft sinking

Artificial freezing of water-bearing soil layers composing a sedimentary deposit can induce frost heave and water migration that affect the natural stress-strain state of the soil layers and freezing process.In the present paper,a thermo-hydro-mechanical(THM)model for freezing of water-saturated soil is proposed to study the effects of frost heave and water migration in frozen soils on the formation of a frozen wall and subsequent excavation activity for sinking a vertical shaft.The governing equations of the model are formulated relative to porosity,temperature,and displacement which are considered as primary variables.The relationship between temperature,pore water,and ice pressure in frozen soil is established by the Clausius-Clapeyron equation,whereas the interaction between the stress-strain behavior and changes in porosity and pore pressure is described with the poromechanics theory.Moreover,constitutive relations for additional mechanical deformation are incorporated to describe volumetric expansion of soil during freezing as well as creep strain of soil in the frozen state.The ability of the proposed model to capture the frost heave of frozen soil is demonstrated by a comparison between numerical results and experimental data given by a one-sided freezing test.Also to validate the model in other freezing conditions,a radial freezing experiment is performed.After the validation procedure,the model is applied to numerical simulation of artificial freezing of silt and sand layers for shaft sinking at Petrikov potash mine in Belarus.Comparison of calculated temperature with thermal monitoring data during active freezing stage is presented.Numerical analysis of deformation of unsupported sidewall of a shaft inside the frozen wall is conducted to account for the change in natural stress-strain state of soil layers induced by artificial freezing.

Analysis of the Change Trends of Temperature and Frost-free Period in Xingtai in Recent 53 Years

[Objective] The changes trend of temperature and frost-free period in Xingtai in recent 53 years were studied.[Method] According to the climate data of Xingtai City and Nangong County in 1958-2010,the changes trend of the temperature,the first and the last frost day,and the frost-free days in Xingtai were studied.The characteristics of the changes of temperature and frost-free days in Xingtai in recent 53 years were studied.[Result] No matter in city or countryside,the annual average temperature was increasing.The climate tendency rates in Xingtai and Nangong were about 0.5 and 0.2 ℃/10 a respectively.Especially,since 1996,the annual average temperature increasing trend was about 1.0 ℃/10 a.The average temperature of the four seasons was also climbing and was similar to the increasing span of the annual average temperature.The annual average temperature increasing span was the largest in winter.And the increase of the annual average temperature in winter was the largest and the increase of the annual average temperature was caused by the increase of the average temperature in winter.The urban annual average temperature was obviously higher than that of the countryside,which reflected the characteristics of tropical island effect.No matter in the city or the countryside,the early frost day,final frost day and frost-free day showed same tendency,namely,the delay of early frost day,advance of final-frost day,extension of frost-free day;the day of urban early frost was late than that of the countryside,and the final frost day was earlier than that of the countryside,the frost-free days were longer than that of countryside and indirectly influenced by urban heat effect.[Conclusion] The study provided theoretical basis for the development and application of thermal resources in Xingtai.

On the Style and Meaning of Robert Frost's “A Servant to Servants”

The greatest characteristic of Robert Frost's poetry is that complex and delicate subjects are embodied in narrative description which seems rather simple. Frost achieves a distinctive grace by combining unique structure and profound meaning together. This thesis explores Robert Frost's"A Servant to Servants"from the point of view on narratology finds out the careful arrangement and unique perspective. The present study concludes that while this narrative poem appears to have a simple organization and to limit itself to colloquial language, at a deeper level it has careful arrangement and expresses profound meaning. While enjoying the poem's vivid narrate, the reader also comes to realize the truth that"A Servant to Servants".

Establishment of Field Sites to Study Frost Heaving and Related Landforms in Southern Yakutia,Russia

Frost heaving processes have been a focus of study since the late 19th century.Factors controlling frost heave development were investigated over several decades.The mechanisms involved were identified based on numerous field and experimental evidences. However,despite this long history of frost

Juxtaposing the Road Taken and Not Taken: An Intertextual Study on Two of Robert Frost’s Poems

By juxtaposing two of Robert Frost's poems—"The Road Not Taken"and"Stopping by Woods on a Snowy Evening"and using stylistic analysis method,this essay tries to make a comparative study on the poems from the perspective of intertextuality,so as to find out a trajectory of Robert Frost's meditations on life and the consistency and connectivity in the crafts and style of his poems,and thus acquire a deeper and multi-angle interpretation on the poems.

Short-day treatment during the growing period limits shoot growth and increases frost hardiness of hybrid aspen plants in the nursery

In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus, frost hardening is usually delayed. To solve this problem, we used a three-week period of short-day （SD） treatment between late July and mid-August. During autumn after frost exposure, frost hardiness （FH） was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore, the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants.

Species of Ice Nucleation Active Bacteria on the Apricot and the Relationship Between Their Activity and Flower Frost

During 1996- 1997, sixty samples were collected from apricot in Hebei Province, from which nineteen ice nucleation active bacterial strains were isolated. Nine stains were identified as Pseudomonas syringae pv. syringae by bacteriological determination, while the others were Erwinia uredovora. Assay of ice nucleation activity (INA) showed the activity of the Pseudomonas strains was higher than that of the Erwinia.According to the number of bacterial cells required to produce one ice nucleus active at - 3℃, four stains was classified as strong ones, three as medium-strong, the remainder as weak. In general, the INA of these strains were regarded as medium-strong. Under stress of Iow temperatures, treatment of INA bacteria can greatly raised relative electric conductivity of petals and permeability of cell membrane. The treated petals showed symptoms of serious frost at - 3 - - 4℃ and had supercooling points of 2 - 3℃ higher than controls. Our results demon strated that INA bacteria are one major factor to incite frost damage to apricot flowers. We may reduce frost injury to apricot during flowering phage through control of INA bacteria.

Improving the Thermal Efficiency and Performance of Refrigeration Systems:Numerical-Experimental Analysis of Minimization of Frost Formation

The frost growth on cold surfaces in evaporators is an undesirable phenomenon which becomes a problem for the thermal efficiency of the refrigeration systems because the ice layer acts as a thermal insulation,drastically reducing the rate of heat transfer in the system.Its accumulation implies an increase in energy demand and a decrease in the performance of various components involved in the refrigeration process,reducing its efficiency and making it necessary to periodically remove the frost,resulting in expenses for the defrost process.In the present work,a numerical-experimental analysis was performed in order to understand the formation process of porous ice in flat plates with different surface treatments and parameters.This understanding is of utmost importance to minimize the formation of porous ice on cold surfaces and improve equipment efficiency and performance.In this context,a low-cost experimental apparatus was developed,enabling an experimental analysis of the phenomenon under study.The environmental conditions evaluated are the temperature of the cold surface,roomtemperature,humidity,and air velocity.The material of the surfaces under study are aluminum,copper,and brass with different surface finishes,designated as smooth,grooved(hydrophilic),and varnished(hydrophobic).The numerical-experimental analysis demonstrates measurements and simulations of the thickness,surface temperature,and growth rate of the porous ice layer as a function of the elapsed time.The numerical results were in good agreement with the experimental results,indicating that the varnished surface,with hydrophobic characteristics,presents greater difficulty in providing the phenomenon.Therefore,the results showed that application of a coating allowed a significant reduction on the frost formation process contributing to the improvement of thermal efficiency and performance of refrigeration systems.

Research status of soil frost-heave theory and frost-heave prediction models

Soil frost heaving is a complex physical, mechanical, and chemical synthesis process. This paper summarizes the frost-heaving theory over half a century, including the capillary theory, the frozen-fringe theory, and those achievements recently made by scholars. In this paper, we also discus researching achievements of the soil-prediction model during the past 40 years, including the water-dynamics model, the rigid-ice model, the segregation-potential model, and the thermo-dynamic model. This summary and discussion will enable readers to understand the latest direction of research; it also summarizes the development of frost-heave prediction models and their advantages and shortcomings.

Comparison of Stem Damage and Carbohydrate Composition in the Stem Juice between Sugarcane and Sweet Sorghum Harvested before and after Late Fall Frost

A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well documented, but information is lacking for sweet sorghum. Three and six commercial cultivars of sugarcane and sweet sorghum, respectively, were selected and evaluated for exposure to a late fall frost (-2.8&degC) in Griffin, Georgia, USA. Under the same controlled environmental conditions in a screen house, the late fall frost induced more damage to sugarcane than sweet sorghum stems. The frost caused damage to sugarcane tissue and for juice to exude from stems, whereas similar behavior was not observed for sweet sorghum. In both sugarcane and sweet sorghum, the glucose/fructose ratio was significantly reduced, but this change may not be totally directly related to the frost effect. Overall, these initial results suggest that sweet sorghum may have a better tolerance to fall frost than sugarcane. Two sweet sorghum cultivars, Grassl and M81E, responded well to the late fall frost, and they can possibly be used as feedstocks for biofuel/bioproduct manufacture in areas susceptible to frosts including northern regions of the Southeastern US.

Threats and Avoidance Measures of Frost Damage of‘Shushanggan’Apricot in the Ili River Valley

[Objectives]To explore the threat factors of frost damage to‘Shushanggan’Apricot in the Ili River Valley,and to provide measures for avoiding frost damage.[Methods]Based on the meteorological data of the Ili River Valley counties and cities during the 12 years from 2010 to 2021 and using the critical low temperature of‘Shushanggan’Apricot as the main factor,we comprehensively analyzed the threats of low temperature in winter in January and late frost in April in spring in the Ili River Valley.[Results]During the 12 years,there were 4 years of low temperature below the critical(-26—-28℃)of‘Shushanggan’Apricot in the Ili River Valley counties and cities in January,accounting for 33.3%,and a total of 59 d.The frequency of occurrence was:Nilka County>Qapqal County>Yining City>Gongliu County>Huocheng County>Khorgos City>Yining County>Tekes County>Xinyuan County.In April,there were 9 years with a low temperature below the critical temperature(-0.6℃)flowering and fruit setting of‘Shushanggan’Apricot,accounting for 75%,and a total of 134 d.The frequency of occurrence was:Nilka County>Tekes County>Gongliu County>Yining County>Huocheng County>Khorgos City>Xinyuan County>Yining City>Qapqal County.The low temperature threats of‘Shushanggan’Apricot suitable cultivation areas were ranked as follows:Nilka County>Gongliu County>Tekes County>Qapqal County>Huocheng County>Yining City>Yining County>Khorgos City>Xinyuan County.Combined with the observation and survey of frost damage on the spot,we comprehensively analyzed and evaluated the cultivation area of‘Shushanggan’Apricot in the Ili River Valley:three counties(Nilka County,Gongliu County,and Tekes County)in the eastern region,except Xinyuan County,suffered frequent late frost damage,are suitable areas for the cultivation of‘Shushanggan’Apricot;three counties and two cities in the western region(Qapqal County,Huocheng County,Yining City,Yining County,Khorgos City)and Xinyuan County in the eastern region are suitable areas for‘Shushanggan’Apricot.The inversion zone at an altitude of 820-1100 in the valley is the superior area for‘Shushanggan’Apricot.[Conclusions]We explored the suitable areas in the origin area of‘Shushanggan’Apricot,and came up with measures to avoid frost damage,to provide a reference for the development of‘Shushanggan’Apricot.

“For the Wood Wakes, and You are Here for Proof”——On the Dialectics of the Ego Construction in Frostian Woods

In Into My Own and My Dream Pang written by Robert Frost,there are two sides in the subject that are at odds with each other:the one that wants to retreat from the worldly matters and the other that calls for others’communication with him.By adopting the psychoanalytic theory of Sigmund Freud and Jacques Lacan,this paper finds that the protagonist’s implicit need for the recognition from others plays a defining role in the construction of his new identity as a hermit.