Annual Temperature Amplitude Research Articles

The synergy between pollution reduction and carbon reduction in Chinese cities and its influencing factors

The synergy between pollution reduction (PR) and carbon reduction (CR) is crucial for cities facing both climate change and environmental pollution in achieving sustainable development. This study evaluates the PR-CR synergy in 295 Chinese cities from 2014 to 2022. Utilizing the improved Tapio Decoupling Principle and the Probit model, the study reveals that: (1) About 51.5 % (152) of the cities demonstrated a synergy between PR and CR. This synergy varied across the years; for instance, 102 cities exhibited it in 2018 and 2020, but only 14 in 2019. (2) The remaining 48.5 % (143 cities) did not exhibit this synergy, largely due to increased carbon emissions. These cities fall into three categories: those affected primarily by air pollution, carbon emissions, or both. (3) Environmental regulation emerged as the most influential factor promoting this synergy, with a significant coefficient of 81.47. Other positive influences included annual precipitation (0.000284), altitude (0.000650), Normalized Difference Vegetation Index (2.024), proportion of secondary industry (0.0168), proportion of construction land area (0.0182), and green patents (0.0000571). Conversely, average annual temperature (-0.0620) and relief amplitude (-0.0705) negatively impacted the synergy. This study enriches the discourse on PR-CR synergy, offering valuable insights for shaping sustainable development policies in cities.

Анализ индекса континентальности климата на территории Северо-Востока России

Analysis of climate continentality is a powerful tool for studying and forecasting weath­er. Considering the continentality index enables determining current climate characteristics and predicting potential changes. This study aims to assess climate change in Russia’s North-East by analysing the continentality index as a complex integral indicator of these changes applicable to vast territories. Although there are many methods for assessing climate continentality, there is no uni­versal methodology. It is proposed in this contribution to employ two of the existing tech­niques. The first focuses on the area’s annual temperature amplitude and geographic latitude. The second involves a calculation of the index based on average January and July tempera­tures, the sum of seasonal precipitation and the area’s latitude. An analysis of the index val­ues of the base and calculation periods leads one to conclude that these values do not change significantly towards either weaker or stronger continentality across the study area.

Combined modelling of annual and diurnal land surface temperature cycles

The land surface's thermal dynamics follows annual and diurnal cycles that are to a large extent controlled by solar geometry. Therefore, annual and diurnal variations of land surface temperature (LST) can be modelled with relatively simple functions controlled by a small number of parameters, typically from three to six. The parameter values of the models can be determined by fitting the respective functions to time series of LST observations. Commonly either annual or diurnal LST variations are modelled or they are modelled sequentially in a two-step process. Here, we combine an annual temperature cycle (ATC) model controlled by the solar zenith angle (ATCsza) with a four-parameter version of the diurnal temperature cycle (DTC) model GOT09: this yields a new annual-diurnal temperature cycle (ADTC) model that simultaneously describes the annual and diurnal surface temperature dynamics. The proposed ADTC model is controlled by physically meaningful parameters: annual minimum temperature, annual temperature amplitude, annual maximum of daily temperature amplitude, mean time of thermal noon and time lag of maximum temperature with respect to summer solstice. Thus, the entire annual-diurnal LST dynamics is described with only five parameters. The new model was tested by fitting it to one year of LST observations obtained for five globally representative tiles of the Moderate Resolution Imaging Spectroradiometer (MODIS), onboard EOS – TERRA and EOS – AQUA satellites. For these tiles, the mean of the root mean square error (RMSE) was 4.2 K. ADTC modelled LSTs were also compared against those obtained with the standard ATC model for the four MODIS overpass times at five representative sites: for these, an overall RMSE of 1.2 K between the two models was obtained. The ADTC derived LSTs were validated against in-situ measurements from three different sites, which yielded an overall RMSE of 3.4 K. Additional investigations over five areas with different land covers (i.e. urban, lake, forest, mountain area and desert) revealed the potential of the ADTC parameters to describe the corresponding surface and climate properties. Since it is driven by solar geometry, the ADTC model reproduces double LST peaks in the tropics naturally. Furthermore, all available observations are modelled simultaneously, which means that a single set of parameters is obtained for each pixel and year.

Thermal Regime of Permafrost on the Western Yamal Under Climate Warming

Climate change observed in the Arctic affects all components of the natural environment, including the state of permafrost. The purpose of this study is to quantify the response of permafrost in various landscapes to changing climatic parameters. The results of long-term field observations (1978-2021) of the thermal regime of permafrost on the Western Yamal are presented. Along with the increase in mean annual air temperatures, the mean annual ground temperature over the past 43 years has increased by 1.5-2.2°C. The maximum increase of permafrost temperature values is observed on flat and polygonal tundra, the minimum increase is typical for flooded lake basins. A decrease in the annual permafrost temperature amplitude was revealed. That is caused by a rapid increase in the air temperature of the cold period, an increase in the snow thickness and an increase in soil moisture in the active layer. The shrinking in ground temperature amplitude at a depth of 5 m is 0.5-3.6°C. A trend of reducing depth of zero annual amplitude from 12-18 m (1980) to 13-16 m (2021) has been revealed.

Co-exposure to highly allergenic airborne pollen and fungal spores in Europe

The study is aimed at determining the potential spatiotemporal risk of the co-occurrence of airborne pollen and fungal spores high concentrations in different bio-climatic zones in Europe. Birch, grass, mugwort, ragweed, olive pollen and Alternaria and Cladosporium fungal spores were investigated at 16 sites in Europe, in 2005–2019. In Central and northern Europe, pollen and fungal spore seasons mainly overlap in June and July, while in South Europe, the highest pollen concentrations occur frequently outside of the spore seasons. In the coldest climate, no allergy thresholds were exceeded simultaneously by two spore or pollen taxa, while in the warmest climate most of the days with at least two pollen taxa exceeding threshold values were observed. The annual air temperature amplitude seems to be the main bioclimatic factor influencing the accumulation of days in which Alternaria and Cladosporium spores simultaneously exceed allergy thresholds. The phenomenon of co-occurrence of airborne allergen concentrations gets increasingly common in Europe and is proposed to be present on other continents, especially in temperate climate.

Experimental investigation of the temperature field of a frost-penetration tunnel based on a whole life cycle laboratory test

Temperature field evolution plays an essential role in anti-freezing design of frost-penetration tunnels, for which temperature data measured throughout the whole life cycle (100 years) are lacking. The spatial and temporal temperature evolution of a frost-penetration tunnel during the whole life cycle was investigated by using a laboratory test. The test model was designed following some basic fundamental assumptions and similarity principles. The proposed test model was validated using typical cases of the long-term evolution of the temperature fields in cold region tunnels. The evolution features, formation mechanisms and influencing factors were deeply discussed. Experimental results of the model test indicate that a frost-penetration phenomenon occurs in tunnels with positive ground temperature and negative mean annual air temperature. Under negative mean annual air temperature, the freezing circle develops radially towards the surrounding rock and simultaneously develops longitudinally along the tunnel after the tunnel breakthrough. The unfrozen surrounding rock freeze yearly and can develop into permafrost. The primary impact factor of frost penetrations is the positive initial ground temperature and negative mean annual air temperature. The mean annual air temperature has an insignificant effect on the annual temperature amplitude of the surrounding rock, whereas the annual air temperature amplitude has a negligible effect on the mean annual temperature.

Biogeography of Fungal Communities Associated with Pinus sylvestris L. and Picea abies (L.) H. Karst. along the Latitudinal Gradient in Europe.

We assessed the diversity and composition of fungal communities in different functional tissues and the rhizosphere soil of Pinus sylvestris and Picea abies stands along the latitudinal gradient of these tree species distributions in Europe to model possible changes in fungal communities imposed by climate change. For each tree species, living needles, shoots, roots, and the rhizosphere soil were sampled and subjected to high-throughput sequencing. Results showed that the latitude and the host tree species had a limited effect on the diversity and composition of fungal communities, which were largely explained by the environmental variables of each site and the substrate they colonize. The mean annual temperature and mean annual precipitation had a strong effect on root fungal communities, isothermality on needle fungal communities, mean temperature of the warmest quarter and precipitation of the driest month on shoot fungal communities, and precipitation seasonality on soil fungal communities. Fungal communities of both tree species are predicted to shift to habitats with a lower annual temperature amplitude and with increasing precipitation during the driest month, but the suitability of these habitats as compared to the present conditions is predicted to decrease in the future.

Response of soil hydrothermal processes within the active layer to variable alpine vegetation conditions on the Qinghai‒Tibet Plateau

Alpine vegetation plays an important role in the thermal stability of the permafrost under a warming climate, as it affects ground hydrothermal dynamics. The response of soil hydrothermal dynamics in the active layer to permafrost degradation under different alpine grassland types is unclear on the Qinghai‒Tibet Plateau. In this study, long-term soil temperature and soil water content in the active layer were monitored in situ from October 2010 to December 2018 at five sites in the Kaixinling permafrost region on the interior Qinghai‒Tibet Plateau along the Qinghai–Tibet Railway. The sites included an alpine steppe (AS), three alpine meadows (AM) with different degrees of degraded vegetation, and an alpine swamp meadow (ASM). Based on field-monitored data, the variations in soil temperature, soil water content, and freeze–thaw processes were examined in the active layer. The response characteristics of the soil hydrothermal processes to climate change were analysed under the different alpine grasslands. The results showed that the duration of the thawing and freezing stages of the active layer of the AMs was shorter than that of the ASM and the AS. The average mean annual soil temperature (MAST) in the active layer of the AM ((−1.25 ± 0.50) °C) was lower than those in the AS ((−0.71 ± 0.39) °C) and ASM ((−0.45 ± 0.57) °C), while the AM had the highest rate of soil temperature increase ((0.2 ± 0.06) °C per year). The annual amplitude of ground temperature in the active layer increased with the transition direction of the alpine vegetation type from ASM to AM to AS. The small surface offset (SO) and thermal offset (TO) (absolute values) indicated that the ground thermal state of the AM was more unstable, as it was more sensitive to the increase in air temperature than the ASM or the AS. Soil properties controlled the distribution of soil water content within the active layer, but vegetation improved the shallow soil structure by producing more belowground phytomass, thus, enhancing soil water content in the 0–30 cm layer. The average soil water content at depths of 0–30 cm was directly proportional (p < 0.05) to the phytomass. Soil water contents at depths of 0–30 cm in the ASM ((37.7 ± 5.3)%) and the AM ((40.8 ± 5.9)%) were significantly higher than those in the AS ((22.7 ± 3.2)%). These results provide valuable insight into the hydrothermal interactions between the degradation of permafrost and alpine vegetation under a warming climate.

Внутригодовая изменчивость температуры приземного воздуха и её моделирование для города Ставрополя

Introduction. It is known that the time course of temperature during the year is seasonal. However, the rates of temperature growth in transition periods are different. This complicates the prediction of such an important parameter, in particular for agriculture, as the air temperature of the surface layer of the atmosphere. Accordingly, the article analyzes the intra-annual variability of air temperature and compares it with a sinusoidal model of the annual temperature course. Materials and research methods. The time series of the air temperature of the surface layer of the atmosphere for the city of Stavropol are considered and the task is to compare the actual and theoretical values of annual amplitudes. In the elementary (sinusoidal) model, this theoretical value turns out to be directly proportional to the annual variance. The time series of temperature differences (inter-monthly changes), the so-called discrete derivatives, is also considered, and the comparison of the usual and discrete derivative of the sine function as an elementary model of the annual temperature course is carried out. A new value is introduced – the standard deviation of variability, which also characterizes the variance, yet not for a number of temperatures, but their differences. Research results and their discussion. It is noted that the theoretical (i.e., valid for the sinusoidal model) and the actual value of the amplitude of the annual temperature course are quite well matched. However, due to non-periodic deviations, the difference between these values can reach 2 °C, which is characterized by asymmetry on the intra-annual variability chart. In addition, the average annual temperature course is considered and its analysis is carried out using discrete derivatives. It is shown that the ratio of the annual temperature amplitude to the amplitude of the discrete derivative of this value is equal to the cyclic frequency of fluctuations of the annual temperature course. Conclusions. The results obtained confirm the possibility of using a sinusoidal model of the annual temperature course (although with some limitations related to the asymmetry and shift of intra-annual peak points). The analysis of the annual temperature course using discrete derivatives and its comparison with the sinusoidal model revealed the features of the average annual intra-annual variability of surface air temperature for the city of Stavropol for the period 1944 – 2022. Sometimes there is a change in the rate of heating or cooling; in rare cases, there is an inversion when considering the time series of average monthly temperatures).

Relationship between Phytocenotic Diversity of the Northeastern Transbaikal Orobiome and Bioclimatic Parameters

The most important spatial patterns of plant cover of the Northern Transbaikalia, its regional features being represented by the structure of altitudinal zonality of the Northeastern Transbaikal orobiome, have been determined in relationship with the climatic factor. The regional climate assessment of the altitudinal belt structure of the plant cover of the orobiome has been performed for typological subdivisions of the highest hierarchic level (phratries of the classes of plant formations) using the BioClim global climate model. Principal component analysis, discriminant and cluster analysis were used to demonstrate that the summer ombrothermic index, continentality and climate moisture indices and the mean annual rainfall of many years are the most significant bioclimatic parameters determining the spatial structure of plant cover in the mountain taiga, subgoletz, mountain tundra and goletz belts. The background communities of orobiome belts develop under the conditions of continental climate (continentality index from 36 to 50). Heat supply parameters, first of all, in the vegetation period, are crucial for the spatial differentiation of altitudinal subelts, characterizing the change of light forest and dwarf pine communities in the subgoletz belt, larch, larch-pine and dark-coniferous forests in the mountain taiga belt. Moisture supply is related to the regional differences in the typological diversity of the belts, which are manifested in the development of more moisture-demanding fir-spruce forests in the low parts of the Patom Highland (rainfall amount more than 450 mm per year) and pine forests in the intermountain basins of the Stanovoy Highlands, existing under the conditions with the maximum annual temperature amplitude and low rainfall levels (up to 400 mm per year).

Numerical investigation of the temperature field and frost damages of a frost-penetration tunnel considering turbulent convection heat transfer

Accurate evaluation of tunnel temperature field plays an essential role in anti-freezing measures of cold-region tunnels. The aim of this study is to establish turbulence-based theoretical models for the temperature field of cold-region tunnels and to investigate the temperature field and frost damages of an actual cold-region tunnel with negative mean annual air temperature. A transient convection–conduction heat transfer model with turbulent flow and phase change was established. The proposed theoretical model was validated using model test results. The temperature field and frost damages of the Daban Mountain tunnel were investigated. The influence of global warming on the temperature field was also deeply discussed. The results indicate that for the Daban Mountain tunnel, the freezing circle develops to the radial surrounding rock and simultaneously develops along the longitudinal direction of the tunnel. Permafrost occurs at the tunnel entrance in the 7th year and along the whole tunnel in the 16th year. The formation rate and maximum freezing depth of permafrost is significantly influenced by the mean annual air temperature. The annual air temperature amplitude has significant effect on the formation rate of permafrost but little effect on the maximum freezing depth. Under global warming, the mean annual temperature of the surrounding rock decreases first and then increases. In the early years, the unfrozen surrounding rock freezes yearly and develops into permafrost. However, as the mean annual air temperature rises, the permafrost gradually degenerates into seasonally frozen rock and the maximum freezing depth decreases yearly.

Meteorological Effects of a Lake in A Permafrost Basin: Difference of Seasonal Freeze–Thaw Cycles in Hovsgol Lake and Darhad Basin, Northern Mongolia

The effects of the present global climate change appear more pronounced in high latitudes and alpine regions. Transitions zones, such as the southern fringe of the boreal region in northern Mongolia, are expected to experience drastic changes as a result. This area is dry and cold with forests forming only on the north-facing slopes of hills and grasslands distributing on the south-facing slopes, making it difficult for continuous forests to exist. However, in the Hovsgol Lake Basin, there is a vast continuous pure forest of Siberian larch (Larix sibirica). In other words, the lake water thawing/freezing process may have created a unique climatic environment that differs with the climate of the adjacent Darhad Basin, where no lake exists. Thus, in order to compare the effect of the thawing/freezing dynamics of lake water and the active layer on the thermal regime at each basin, respectively, temperatures were simultaneously measured. The Darhad Basin has similar latitude, topography, area, and elevation conditions. As expected, the presence of the lake affected the annual temperature amplitude, as it was 60% of that in the Darhad Basin. The difference in the seasonal freeze–thaw cycles of the lake and the active layer caused a significant difference in the thermal regime, especially in winter.

Increases in the temperature seasonal cycle indicate long-term drying trends in Amazonia

Earth System Models project a wide range of rainfall changes in the Amazon rainforest, and hence changes in soil moisture and evapotranspiration. Hydrological changes are heterogeneous, meaning local measurements are too sparse to constrain projections of large-scale hydrological change. Here we show that changes in the amplitude of the temperature seasonal cycle are strongly correlated with annual mean evaporative fraction (surface latent heat flux as a fraction of surface net radiation) changes, across reanalyses and Earth System Model projections. We find an increase in annual temperature amplitude of 1 °C is associated with a reduction in evaporative fraction of up to 0.04. The observed temperature seasonal cycle amplitude increase (0.4 °C) over the last three decades implies Amazon drying, determined in the absence of soil or energy flux measurements, matches Earth System Model simulations of the recent past. Additionally, Earth System Models predict further temperature seasonal cycle amplitude increases, suggesting drying will continue with future climate change.

Climatic gradients of biological properties of zonal soils of natural lands

It has been found that climatic conditions affect the biological properties of soils on which their fertility and sustainability depends. Most studies on the impact of climate change on soil properties are based on the results of model experiments, which focus on changes in one, rarely two factors. In these experiments the direct influence of climatic factors on soil properties is traced, but in natural conditions the climate has not only direct influence, but also indirect, influencing other factors. Therefore, it is very important to study the response of soils to climate change in the geographical aspect. This knowledge will allow us to make more accurate predictions of soil fertility, sustainability, quality and health under possible climate change. Two transects crossing the North Caucasus in latitudinal and meridian directions have been investigated. The first transect is latitudinal one, its general direction is from west to east, it is 800 km long, passes through plains, dry plains and semi-deserts and reflects the increasing continentality of the climate from west to east. The second transect is meridional, which is 1000 km long, crosses the plains, forest-steppe, deciduous and coniferous forests as well as mountain meadows in a north–south direction. It reflects climate changes during the transition from plain natural zones to the mountainous zones of the Caucasus Mountains. The patterns of dependence of biological properties were revealed for Chernozems, Kastanozems, Calcisols, Phaeozem, Cambisols, Leptosols zonal soils of the North Caucasus: the number of fungi and bacteria, activity of catalase (CA), dehydrogenase (DH), polyphenol oxidase (PPO), peroxidase (PO) and invertase (IN), soil organic carbon (SOC) content versus climatic parameters (temperature, precipitation, climatic indices and coefficients). The factors limiting biota and biological activity of soils have been identified. The maximum dependence of their biological parameters is typical for extreme climatic conditions. The highest correlation of biological parameters of soils was noted with the annual precipitation and temperature amplitude. The maximum values of the total biological activity, taking into account the entire soil profile, were noted in warm and sufficiently humid climatic conditions, where deep Haplic Chernozem Pachic are formed. When the moisture conditions change, both towards aridization and humidization, the total biological activity of soils decreases, which is calculated for the entire thickness of the soil to the rock. SOC is an accumulative indicator of biological activity, therefore it most closely correlates with most of the studied climatic indicators. Among soil enzymes, a close dependence on climatic parameters was established for CA. IN, DH, PPO and PO have more complex non-linear relationships with climatic conditions.

Temperature field spatio-temporal law and frozen-depth calculation of a tunnel in a seasonally frozen region

The freezing-thawing process in seasonally frozen regions may cause damage to underground structures, especially tunnels. The temperature field and frozen depth can provide reference for tunnel frost damage treatment. Based on the Banshiling tunnel in Northeast China, the spatio-temporal distribution of the tunnel temperature field was revealed using a self-designed intelligent monitoring system. Combined with the temperature field characteristics, a modified formula for predicting frozen depth was established considering the unfrozen water content. Also, the rationality of the modified formula was verified using an example. The calculation error of the modified formula is 1.23% to 15.63%, which is highly consistent with the observed value. Comparing the spatio-temporal distribution of temperature field and frozen depth, they have high consistency. And both them are approximately symmetrically distributed along the longitudinal direction of the tunnel: the lower the temperature, the greater the frozen depth, and the smaller the longitudinal variation along the tunnel. The sensitivity of frozen depth to geographical factors and parameter factors was explored to clarify the influence of different factors on frozen depth. The results show that the sensitivity of the frozen depth to latitude is much greater than that to altitude, and the sensitivity of the frozen depth to different calculation parameters is in the order of mean annual temperature, initial ground temperature, water content, annual temperature amplitude, and thermal conductivity.

Meta-analysis of outdoor thermal comfort surveys in different European cities using the RUROS database: The role of background climate and gender

Systematic comparisons of subjective thermal assessments among different geographical locations and between different genders are quite limited. This paper presents a meta-analysis using the data of comprehensive European outdoor thermal comfort (OTC) surveys. The aim is to reveal the common traits and the major differences regarding the subjective thermal perception and sun preference of residents in different European cities while taking great emphasis on the role of genders. The analysis relies on the RUROS (Rediscovering the Urban Realm and Open Spaces) project which was conducted in seven European cities, and the Hungarian OTC project. Only acclimatized local residents were considered to reflect the geographical and possibly cultural differences among the population of the investigated cities. The resulted neutral temperature values – expressed in terms of Physiologically Equivalent Temperature (PET) and determined by means of regression analysis – showed strong correlation with the long-term climatic characteristics, and narrower neutral zone was found at those locations where the annual temperature amplitude was small. Inhabitants of sunny and warm cities did not prefer more sunshine even when the actual sunshine value was low, while where the annual amount of sunshine was low the people showed greater sun preference. European women were found to perceive the thermal conditions as neutral under slightly warmer conditions than men and showed greater sensitivity to the changes of the environmental conditions. This was evidenced by narrower neutral PET zone of females and stronger correlation between their sun preference and the actual value of solar radiation.

Short-Term Meteorological and Environmental Signals Recorded in a Firn Core from a High-Accumulation Site on Plateau Laclavere, Antarctic Peninsula

High-accumulation sites are crucial for understanding the patterns and mechanisms of climate and environmental change in Antarctica since they allow gaining high-resolution proxy records from firn and ice. Here, we present new glacio- and isotope-geochemical data at sub-annual resolution from a firn core retrieved from an ice cap on Plateau Laclavere (LCL), northern Antarctic Peninsula, covering the period 2012–2015. The signals of two volcanic eruptions and two forest fire events in South America could be identified in the non-sea-salt sulphur and black carbon records, respectively. Mean annual snow accumulation on LCL amounts to 2500 kg m−2 a−1 and exhibits low inter-annual variability. Time series of δ18O, δD and d excess show no seasonal cyclicity, which may result from (1) a reduced annual temperature amplitude due to the maritime climate and (2) post-depositional processes. The firn core stratigraphy indicates strong surface melt on LCL during austral summers 2013 and 2015, likely related to large-scale warm-air advection from lower latitudes and temporal variations in sea ice extent in the Bellingshausen-Amundsen Sea. The LCL ice cap is a highly valuable natural archive since it captures regional meteorological and environmental signals as well as their connection to the South American continent.

Analysis of Low-Power Boilers Work on Real Heat Loads: A Case of Poland

The paper presents the methods of determination of the actual operation of solid fuel heating boilers in Poland. The analysis was based on an average annual distribution of the actual power outputs of the solid fuel heating boilers operated in four selected locations in Poland. Based on said data, three characteristic percent shares have been estimated of the nominal power outputs, at which the heating boilers in Poland operate throughout the year (divided into four characteristic portions—the seasons of the year). Additionally, for the analysis, the authors took into account the average annual temperature amplitude and the annual air quality information for the discussed locations and analyzed 30 solid fuel heating boilers in terms of their performance in the laboratory certification tests. In the final stage of the investigations, the authors initiated laboratory tests on the application of the combustion quality analyzers and their potential benefits.

Revisiting climatic features in the Alaskan Arctic using newly collected data

Climatic features in the Alaskan Arctic have typically been analyzed using data from the limited National Weather Service stations. However, the increasing availability of in situ data in this area allows a more comprehensive understanding of recent changes. This study used newly collected data from 41 stations to investigate climatic features and recent changes in the Alaskan Arctic from the mid-1940s to 2018. We found that the mean annual air temperature (MAAT) ranged from –11.0 to –6.4 ∘C, annual amplitude of air temperature (AAAT) ranged from 16 to 22 ∘C, annual precipitation ranged from 85 to 300 mm, and annual mean snow depth ranged from 13.5 to 34.5 cm during 2007–2012. Compared with data since the late 1980s, MAAT increased by $\sim $ 2 ∘C near the coastline whereas AAAT did not significantly change. Changes in annual precipitation were complex among stations but showed a considerable increase in precipitation, snowfall, and snow depth during the cold months. The number of snow cover days declined, whereas the number of snowfall days increased at both Barrow and Kuparuk. This increase in snowfall events may be attributed to the declining sea ice concentration, which may enhance hydrological cycles. The observed bulk density of fresh snow was around 40–80 kg/m3 and declined from the mid-1980s to the late-1990s, then increased until the end of the study period. This expanded in situ dataset provides a more comprehensive understanding of climatic conditions in the Alaskan Arctic and confirms rapid changes during recent decades. This study may also serve to validate and benchmark high-resolution climate models.

Differentiation of the Southern Transbaikalia territory in the thermo-freezing regime of soils

Broad variations in the soil temperature are characteristic of the southern Transbaikalia. The soil temperature varies in the ranges of -2,5 ÷ -19, -0,5 ÷ -12,5 and 2,8 ÷ -3,2 °C at the depths of 0.2, 0.8 and 3.2 m respectively. The mass of data is classified into four groups that are characterized as moderately cold, cold, very cold and severe based on qualitative characteristics of their thermal conditions. The moderately cold conditions of soils (A) occur at the south-eastern shore of Baikal lake. Cold conditions of soils (B) are scattered over all the territory and usually occur at near-river descents and valleys of hollow type. The very cold conditions of soils (C) are most widely spread in the Southern Transbaikalia. They can be considered as the background conditions of the territory considered. The severe conditions (D) are met in the form of small dispersed patches only. Based on the method of conjugate analysis of mutually related landscape components, a cartographic model is developed that can be pertained to the ecological direction in cartography. Analysis of annual temperature variations at the soil profile depths and of its vertical distribution in all months of a year revealed some new regularities. Firstly, the periods of near-zero temperatures and their durations in different soil layers were determined and, secondly, annual temperature amplitudes were fixed in soil profiles of various cooling and freezing conditions.