Negative Air Temperatures Research Articles

Microclimate of Brown Bear (Ursus arctos L.) Dens and Denning Area.

The aim of this study was to determine the microclimate of brown bear dens depending on their size, their status (active or inactive), and the location of the den. The study included five dens of different sizes and locations in the Velebit Mountains, in the Dinaric Alps. The measurements of air temperature (°C) and relative humidity (%) in dens and the forest stands were carried out over 182 days. The absolute minimum air temperature in inactive dens was between -2.88 °C and -0.38 °C and belonged to the dens with shorter tunnels and without chambers. The exception was inactive den 1, which was situated in a thermophilic forest. No negative absolute minimum air temperatures were recorded in active dens. The absolute minimum air temperatures in the forest stands were lower than in the dens. The relative humidity was significantly higher in all dens than in the forest stands. Dens with a large entrance opening and a short tunnel were strongly influenced by the local microclimate of the forest stand. The greatest temperature difference (den-forest) was between elongated dens with chambers and the associated forest stand, while the smallest temperature differences occurred in dens with a short tunnel, without a chamber, and at the northern exposure. The greatest differences in relative humidity (den-forest) were found in dens with chambers. The den temperatures correlated with the air temperatures in the forest stands.

Развитие модели динамики снежного покрова Гидрометцентра России

Conceptual models of runoff formation used in the operational practice of hydrological forecasting by the Hydrometeorological Center of Russia include simplified parameterization of snow cover dynamics based on the use of snow cover melting coefficient, water-retaining capacity of snow and secondary freezing of meltwater in case of return of negative air temperatures. This schematization of the process is well established for the reliable calculation of the snow water equivalent for subsequent use in the calculation of meltwater inflow to the catchment surface and the calculation of streamflow characteristics. At the same time, the lack of calculation of snow density and snow height in the used schematization restricts the use of schemes for calculating of soil freezing depth in hydrological models, which seems to be extremely important for modelling runoff on mid-latitudes rivers, i.e. for the most Russian rivers. To overcome this disadvantage, the snow density and snow height parameterization was added to the calculation scheme of the model, which was verified using Roshydromet’s snow measurement routes data and shown a good and satisfactory quality of modeling of model characteristics.

Агроклиматическая оценка периода перезимовки озимой пшеницы в Центрально-Черноземном экономическом районе

This study was conducted in order to identify the most significant, in terms of influence, agroclimatic indicators of the overwintering period for winter wheat in the territories of the regions that are part of the Central Black Earth Economic Region. For this purpose, meteorological data on average, minimum and maximum air temperature, precipitation and snow cover height for the period from 1993 to 2022 were used, and a correlation and regression analysis of the dependence of the yield of this crop on the calculated indicators was carried out. During the analysis, statistically significant dependences of winter wheat yield on a number of agroclimatic indicators of the overwintering period were considered, revealed when using the Fisher criterion and estimating the P-values of the coefficients of the regression equation. According to the results of the analysis, the most significant indicators of the overwintering period are: the average air temperature for the coldest month and the coldest five-day period, the duration of the period between the dates of a steady transition of air temperature through 0℃ in autumn and spring, as well as the sum of negative air temperatures between these dates. The results obtained can potentially be more visible when using a larger amount of data, as well as when performing multiple regression.

Determination of occurrence of atmospheric blockings over the Caspian Sea region in winters of 1959–2022, and influence of them on the ice regime of the Northern Caspian Sea

The ice regime of the Caspian Sea has pronounced influence on the heat and moisture exchange of the reservoir with the atmosphere, the state of the ecosystem, as well as human marine activities, including shipping, fishing, construction of hydraulic structures, etc. Consequently, the development of existing ideas about the causes of changes in the characteristics of the ice regime of such water bodies is actual and socially significant problem of limnology, hydrometeorology, ecology, and navigation. This study was aimed at determination the frequency of occurrence of atmospheric blockings over the Caspian region with standings longer 5 days in winter period of 1959–2022, and investigation of influence of them on the ice regime in the Northern area of the Sea. The following information and data were used: changes in hourly mean values of atmospheric pressure at the sea level, geopotential of isobaric surfaces 850, 500 and 300 hPa, presented in the ERA5 reanalysis; and observational data on air temperature and ice cover from hydrometeorological stations located in the Caspian region of Kazakhstan and Russia. It has been established that in the winter during a long standing of atmospheric blockings the mean daily air temperatures noticeably drop. The values of all the studied characteristics of every atmospheric blocking which occurred in 1959–2022 were estimated as well the influence of them on the ice regime in the North of the Caspian Sea was analyzed. The relationship between a decrease in the frequency of atmospheric blockings (AB), sums of negative air temperatures on its coasts, and the ice cover thickness in the corresponding areas of coastal waters has been revealed in the region. The longer the total AB duration, the lower is the air temperature, and the ice thickness in February is larger.

Влияние температуры на терморегуляцию и активность соболя (Martes zibellina L. 1758)

The purpose of the study is to identify the dynamics of thermoregulation and activity of the sable in the process of changing environmental temperature. Objectives: assessment of the dynamics of changes in the temperature of sable fur at positive and negative air temperatures; studying the dynamics of physical thermoregulation of sable due to convection and heat radiation; the influence of low air temperatures on the activity of the sable and the body’s costs of supporting vital functions. During long-term observations of sable activity, data were collected on the length of the animals’ daily movement in the Turukhansk and Evenk Districts of the Krasnoyarsk Region under accompanying weather conditions. Data on the dynamics of sable body temperature depending on the ambient temperature were collected in the Krasnoyarsk Flora and Fauna Park “Roev Ruchey”. The temperature period of the surface layer of air is covered from –30 to 30 °C. The pyrometer Testo 830-T1 was used. These studies expand and clarify ideas about the influence of the temperature factor on aspects of sable activity at low air temperatures in natural habitats. Analysis of data on the dynamics of physical thermoregulation of sable due to convection and heat radiation revealed temperature ranges of optimum for sable. Temperature optimum – 0 °C. The range of favorable temperatures for moving sable is from –5 to –25 °C. The largest number of sable tracks was recorded at a tempe¬rature of –15 °C. The data obtained make it possible to estimate the costs of the animal’s body to support vital functions during the winter period. At an air temperature of –15 °C, a sable in a calm state loses 2.78 Kcal per hour. Under favorable conditions, the predator spends 3 to 4 hours searching for food, losing 33,400 calories at a time.

Formation of subaerial taliks in Larsemann hills, princess Elizabeth land, East Antarctica

This study presents a mathematical model of heat and mass transfer for modelling the formation and evolution of taliks in the upper subsurface of the Larsemann Hills in East Antarctica. Four simulation scenarios were considered. The first one showed that thawed areas cannot form under snowfields. The second and third scenarios demonstrated the taliks did not form if the snow melted immediately after set the positive air temperatures and covered the surface 20 days before the set of negative air temperatures or immediately after that. According to the last scenario, talik forms when snow cover persists even with positive air temperature, and snow falls before the air temperature becomes negative. Modelling demonstrates that taliks in the Larsemann Hills exist, but they are mostly in an unstable state.

Warming Climate-Induced Changes in Lithuanian River Ice Phenology

Due to rising surface air temperatures, river ice is shrinking dramatically in the Northern Hemisphere. Ice cover during the cold season causes fundamental changes in river ecosystems and has important implications for nearby communities and industries. Changes caused by climate warming, therefore, affect the sustainability of key resources, livelihoods, and traditional practices. Thus far, too little attention has been paid to research into the phenomenon of river ice in the Baltic States. Since the observational data of the last sixty years are currently available, we took advantage of the unique opportunity to assess ice regime changes in the gauged rivers by comparing two climatological standard normals. By applying statistical methods (Mann–Kendall, Pettitt, SNHT, Buishand, von Neumann, and Wilcoxon rank sum tests), this study determined drastic changes in ice phenology parameters (freeze-up date, ice break-up date, and ice cover duration) of Lithuanian rivers in the last thirty-year period. The dependence of the selected parameters on local climatic factors and large-scale atmospheric circulation patterns was identified. It was established that the sum of negative air temperatures, as well as the North Atlantic Oscillation, East Atlantic, and Arctic Oscillation indices, have the greatest influence on the ice regime of Lithuanian rivers.

Structure and Microhardness of Constructional Steel after Ultrasonic Impact Treatment at Negative Air Temperatures

The paper investigates the effect of ultrasonic impact treatment on the structure and microhardness of constructional steel 10G2FBYu (GOST). Ultrasonic impact treatment of these steel was carried out an air temperature of -30 °C.

Design of an active subsurface system thermal energy supply to the bio-vegetation complex

The efficiency of vegetable production in closed ground structures is directly dependent on the costs associated with creating artificial, controlled conditions for growing plants during the period when cultivation of them in open ground due to climatic conditions is impossible. One of the indicators of the economic efficiency of vegetable production in protected soil structures is labor costs and funds per 1 hundredweight, per 100 rubles of gross production, as well as energy costs, including thermal energy. Usually, solar, biological, electric and other types of heating are used to supply thermal energy to cultivation facilities, each of which has its own disadvantages. The bio-vegetation complexes structurally distinguished by the fact that cultivation beds are located on various foundations make it possible to create an active underground heating system. The paper presents the development of a design for an active subsurface system for thermal energy supply to the bio-vegetation complex and calculations of the main parameters of the system for autonomous operation of the object at negative outside air temperatures. The design of the active subsurface system for thermal energy supply to the bio-vegetation complex is proposed in the form of a heat-accumulating sand-gravel mass, inside of which there are heat supply circuits with a heat carrier closed with a concrete screed on top. The calculation of energy consumed by the active sub-ground thermal system providing optimal parameters of the growing medium corresponding to biological rhythms of plant development at low outside air temperatures is also presented. The study determines the area of the photovoltaic unit and the number of photovoltaic modules for generating electric energy in order to cover the spent thermal energy and the effective functioning of the active subsurface system for thermal energy supply to the bio-vegetation complex.

ПЕРЕВОЗКА ЖЕЛЕЗНОДОРОЖНЫМ ТРАНСПОРТОМ ВЯЗКИХ НЕФТЕПРОДУКТОВ В ЗИМНИХ УСЛОВИЯХ ПРИ ПРИМЕНЕНИИ ПРИНЦИПОВ КАТАЛИТИЧЕСКОГО РАЗОГРЕВА

The article investigates the problem of unloading solidifying petroleum products (such as boiler fuel oil) at a medium-capacity drain site. It is accepted that a filling train of 45 specialized 67-ton tank cars is placed under the drain, the train is en route for 7-8 days at negative air temperatures (up to -20 °C). Usually, from 3 to 5 tank cars are simultaneously put under unloading at a medium-capacity drain site, up to 10-12 hours are spent on heating them; for unloading, emptying the drain site and installing the next 5 tank cars - 2-2.5 hours more. The rest of the tank cars are put on the access roads, waiting in line. The oil product in them, initially having a low temperature, keeps cooling and passes into a highly viscous state. In addition to the delivery time (7-8 days), the train, as a rule, is under the unloading operation for 8-10 more days. In the method of processing proposed by the authors, tank cars can be heated already at the idle stage on the access roads, and the discharge is carried out at the drain site. In this case, the unloading time of the filling train is reduced to 15-20 hours.

Climatic influence on productivity of walking excavators and bulldozers in stripping in gold placer mining

The state and mineability of placer gold reserves and resources in the Russian Federation is reviewed. Judging from wide application of dragline excavators in peat cutting, it can be effective to use draglines in placer mining at depths up to 50 m due to the much lower cost of stripping compared to the other methods. In this case, it is possible to apply various schemes of direct dumping and wider employment of draglines in actual mining. It is noted that one of the highest influences on productivity of draglines and bulldozers during stripping is the presence of seasonal and perennial frost. Two groups of factors to decrease productivity of walking excavators and bulldozers at negative air temperatures are proposed. The conclusions are made about the difficulty of determining frozen ground cuttability due to the peculiarities of overburden sediment formation and because of deficient detailed studies into the properties of rocks, which govern their strength characteristics during freezing. The less labor-intensive method of calculating productivity reduction of walking excavators and bulldozers during stripping is proposed as the determination of hourly productivity reduction patterns by mathematical methods describing the random nature of phenomena, in particular, by the correlation method. The equations of the hourly productivity reduction of draglines and bulldozers depending on average monthly negative air temperature and the hourly capacity reduction factor as function of seasonal permafrost thickness and perennial permafrost cross-sections in overburden face are derived. It is noted that seasonal freezing governs reduction in productivity of excavators and bulldozers at the beginning of the warm period of the year until the permafrost is completely thawed. Stefan’s formula is suggested, according to which it is possible to calculate the depths of seasonal freezing of peat depending on the average monthly air temperature quite reliably.

Response of Seasonally Frozen Ground to Climate Changes in the Northeastern Qinghai-Tibet Plateau

The effects of climate change on permafrost have been well documented in many studies, whereas the effect of climate change on seasonally frozen ground (SFG) is still poorly understood. We used the observed daily freeze depth of SFG and environmental factors data from the period 2007–2016 to examine the seasonal and inter-annual variation of SFG. We quantitatively evaluated the effects of environmental factors on SFG using a boosted regression tree analysis. The results show that, on a seasonal scale, the lower layer soil frost starts freezing in mid-November, with the maximum freeze depth occurring in late March (209 cm), and then begins to thaw in both the lower and upper layers. We identified four stages of the freeze-thaw cycle: the non-frozen phase, initial freezing, deep freezing, and thawing. Furthermore, the thawing process of SFG mainly took place in the upper layer, but the freezing rate of the lower layer from mid-November to early February was similar to the thawing rate of late April to late June. On the inter-annual scale, the maximum freeze depth showed a significant increasing trend (p < 0.05). However, the freeze-thaw duration declined significantly (p < 0.05), which was correlated with the decrease in the period when surface soil temperature is below 0°C. The mean soil temperature and soil heat flux were the most important environmental indicators affecting seasonal variation of SFG depth, and the cumulative negative air and soil temperatures were the dominant factors affecting inter-annual variation of maximum freeze depth. Our results might provide insight into predicting hydrological and ecological responses to future climate change in frozen-ground regions.

Experience in construction of monolithic layers of road pavement at sub-zero air temperatures

Introduction. Increasing the durability of road structures and extending the construction season for the installation of monolithic road pavements are urgent tasks. Non-rigid road pavements are of particular interest. Replacing the bases of granular materials (crushed stone, gravel, etc.) with monolithic ones reduces the material consumption of the road surface by 20-50%, the cost of construction works by up to 45% and increases the service life of roads by 1.5-2 times. The extension of the construction season for the installation of monolithic bases contributes to an increase in the pace of construction, a more rational use of road construction equipment, securing highly qualified specialists at the enterprise and reducing overhead costs. A multi-tonnage waste having independent binding properties is of particular interest, for example, belite sludge of alumina production. The article is devoted to a comprehensive study of the physical mechanical and technological properties of natural belite sludge in order to use it for the making of monolithic layers of road and airfield pavement in winter, without the introduction of antifreeze additives.Materials and methods. The freezing temperature of the belite sludge of minus 2 ° C was determined by the thermoelectric method. Its compactibility in the range of negative temperatures, the ability to restore the destroyed structure after re-compaction, the regularities of cooling of the material during technological operations for the construction of structural layers in winter are studied. The compaction was studied by pressing samples from sludge of optimal humidity, at its temperatures from 20 to minus 10°C. The study of the processes of structure formation of sludge and sludge crushed stone materials consisted in studying the kinetics of hardening of samples stored in climatic chambers that simulate changes in average monthly air temperatures in an annual cycle (from 20°C to minus 20°C) and in natural conditions (outdoors). In parallel, thermographic and electron microscopic studies of neoplasms in the hardening material were performed. To study the regularities of the cooling of the sludge layers, a laboratory experiment was conducted that simulates two-way (top and bottom) freezing of the material in a climatic chamber at temperatures of minus 10, minus 15 and minus 25°C.Results. A complex of unique physical chemical and technological properties of natural belite sludge has been identified, which consist in maintaining the initial density and activity after freezing, the ability of sludge and sludge crushed stone materials to harden at negative temperatures, a reduced freezing temperature of minus 2°C, good compaction in the range of negative temperatures (up to minus 6°C). The temperature and technological parameters of the sludge preparation for the production of works in winter are investigated. The regularities of sludge cooling in the technological process for the construction of structural layers in winter are studied. A technology has been developed for the making of monolithic layers of the road pavement made of belite sludge and crushed stone materials at negative air temperatures up to minus 20°C. The practical experience of the belite sludge use in the construction of roads in 2-4 road-climatic zones is summarized.

Justification for automobile transportation technology of limited coal shipments in the city

Introduction. In the economy of states, one of the constant tasks remains to ensure the urgent needs of the population, in an autumn-winter period in cities and settlements, the task of providing fuel (coal) to households is highlighted. The demand for coal is limited by solvency and distributed over the entire period of negative air temperatures. Hence, the supply of coal for the period of heating of dwellings is formed, in many cases, by purchasing lots of coal, representing a share of the total demand during the specified period. The purpose of this work is to find reasonable answers on the use of transportation technologies for limited shipments of goods in cities.Materials and methods. The solution to the problem was carried out within the framework of operational planning for the transportation of limited shipments of coal for the population throughout the city on the basis of the concept of an approach to building a general theory of truck systems functioning for motor transport shipping network, using a regulatory approach when calculating transportation costs, descriptive models of the car’s operation in micro- and delivery motor transport shipping network.Results. Through mathematical modelling, reasonable values of operational plans for the transportation of limited shipments of coal in cities by machine technology and delivery were obtained. Regulatory approach to cost calculation, electronic database of road transport industry updated at the date of calculation. Software and mathematical support for calculating the costs of cargo transportation as part of models of micro and especially small motor transport systems made it possible to reliably determine the planned values of transportation costs by machine technology and delivery.Discussion and conclusion. The advantage of using delivery technology in the conditions under consideration has been established, when transporting coal by road using the case of a city.

Improving the efficiency of agricultural land use in the South-East of the Saratov region in the face of climate change

The article analyzes climate change in the dry steppe regions of the Saratov region for the period from 1899–2018. and crop yields for the period from 1933–2018. The trends of improving the moisture supply of the territory in 1902–2007 are revealed. and its aridization in 2008–2018. Noted: an increase in the average annual air temperature and the sum of active air temperatures (≥10°C); decrease in the amount of winter negative air temperatures; increase (by 8–10 days) in the duration of the growing season (which is favorable for late-ripening varieties and hybrids); a decrease in soil freezing (due to which the volume of spring runoff of steppe rivers decreased from 50–95 to 3–19% of the total volume). The need to adapt crop production to changing climatic conditions is emphasized. Based on studies of the relationship between the cycles of 11 and 22-year solar activity (SA) with the amount of precipitation and the yield of grain crops in the Novouzensky district of the Saratov region, a forecast of favorable and unfavorable years for the cultivation of cereal crops was developed, which allows taking into account possible climatic risks and taking the necessary management decisions.

The effect of negative air temperatures and humidity on the photosynthetic apparatus functioning in some species of Oleaceae family

The characteristics of the photosynthetic apparatus functioning in the leaves of some evergreen species of Oleaceae family depending on the cold periods` weather conditions on the southern coast of Crimea are presented in this work. It has been revealed that changes in PSII are species-specific. Low air humidity in combination with negative air temperature promotes a significant decrease in frost resistance in the studied Olea and Osmantus genotypes. However, in Olea europea genotypes, changes in the PSII parameters under the simulation of winter desiccation approximated sublethal limits. The photosynthetic apparatus in L. lucidum species was more sensitive to a decrease in air temperature under conditions of relatively high air humidity. The development of the stress state in this species was accompanied by an increase in energy losses in the process of energy transfer from light-harvesting complexes. With the onset of frosty weather, a significant decrease in the chlorophyll a/b ratio was noted in all the studied genotypes. After the stress pressure, Olea europea cultivars and Osmantus spp. showed an increase in chlorophyll amount, in contrast to L. lucidum, in which the ratio of photosynthetic pigments remained low.

САМОВОЗГОРАНИЕ УГЛЕЙ В УСЛОВИЯХ КРИ0ЛИТ030НЫ

Taking into account the prospects for the growth of coal production in the conditions of the North-East, the countries require further development of research to more reliably justify measures to prevent endogenous fires in the permafrost zone, which cause serious economic damage and worsen the environmental situation due to the release of large amounts of toxic gases. The authors have studied the chemical activity and tendency to spontaneous combustion of coals in the permafrost zone. The effect of ambient temperature on the dynamics of oxidative processes in coal accumulations is shown. These studies have identified the main factor in preventing the endogenous fire hazard of coal deposits in the North-East of the country, which consists in maintaining negative or low air temperatures to prevent the intensification of oxidative processes in the coals of the permafrost zone. In laboratory conditions, the influence of physical and chemical factors on the process of spontaneous combustion of frozen coals was studied. Field experiments were carried out on many coal mines in the permafrost area. A system analysis and generalization of domestic and foreign methods of prevention of spontaneous combustion of coals has been carried out. Antipyrogenic compositions have been proposed to reduce the oxidizing ability of coals

Method of optimizing the operation of a water source heat pump

The paper presents the principle of operation of a water heat pump that periodically uses the heat of the phase transition of water to supply the lower heat source. The device was built on the basis of patent no. PL209839. In the patent, the problem of icing of the lower heat source (evaporator) was solved, which caused periodic shutdown of the heat pump in traditional solutions. As a result, there was a break in the heat supply. The phenomenon of icing is analogous to the phenomenon of frosting that occurs in the case of air heat pumps operating during the period of negative outside air temperatures. In this article, a system is proposed that will control the operation of the device based on a calculation algorithm that takes into account the temperature and evaporation pressure. In the case of the analyzed heat pump design solution, these values directly affect the value of the obtained COP energy efficiency coefficient. In addition, the publication specifies the operating factors affecting changes in temperature values and evaporation pressure. They were taken into account during the selection of automation and the algorithm controlling the operation of the device.

Features of the dynamics of ice formation in Western Yakutia

Ice formation may cause quite serious and even catastrophic complications during the construction and operation of various types of engineering facilities. Forming on the surface of the earth, ice affects the surrounding landscape, changes the morphology of river valleys, amount of solar radiation, temperature, evaporation, condensation. Accumulating underground runoff in winter, ice redistributes it and regulates the surface runoff giving water reserves in spring and summer that were abandoned during long winter. The paper considers the dynamics of ice formation located in the basin of an unnamed watercourse, the left tributary of the Taryng-Yuryakh River. The main purpose of the study is to identify ice, observe annual changes in its shape, volume, area and power. The research area is located in the south-west of Yakutia. The length of the stream is 5 km, the watershed area is 7.62 km2. The water regime is characterized by spring floods, summer floods, long and low-water summer and winter low water, stable ice supply. According to the results of the study, the correlation between the maximum ice area, the value of atmospheric precipitation of the previous year and the sum of negative average monthly air temperatures was not established.

Prediction of fecundity of livestock by the level of adaptability in the ecological and climatic conditions of the Southern Urals

The article presents the results of studies on the natural resistance of castrated bull calves of Simmental breed in the Southern Urals and half-blood Holstein crossbreeds. The aim of the present study was to determine the adaptability of purebred and cross-breeding animals to a sharply continental climate when keeping them in an open feeding area. Assessment of the body’s response to the influence of negative air temperatures was carried out according to the indicators of the natural resistance of the humoral and cellular parts of the immune system and hair condition – regularity of its shift, length, density and fractional composition. Significant differences in the determined indicators were revealed both depending on the genotype and on the season of the year. Simmentals exceeded their cross-breed peers in hair density from 1 cm2 of skin, weight, and hair length. These differences are most pronounced in winter. Assessment of the humoral link of natural resistance showed significant intergroup differences. Simmental bull calves exceeded cross-breed peers in bactericidal blood activity depending on the season of the year by 1.28–2.87 %, in terms of lysozyme content – by 2.9–7.1 %. Intergroup differences were also revealed in the assessment of cellular factors of natural resistance. In spring, the activity of neutrophils increased in comparison with autumn and winter months in Simmental bull calves 6.4 and 7.3 times. The highest value of the phagocytic index was noted in winter period – 11.4–11.9 %. In summer, it decreases slightly. Intergroup differences in these indicators are slightly expressed.