Air Temperature Variations Research Articles

Energy conservation of HVAC systems in isolation rooms using heat pipe heat exchangers

Isolation rooms are crucial in healthcare facilities to prevent the spread of infectious diseases. Infectious diseases can be transmitted to humans from humans or through animals known as zoonoses. With the increase in the number of COVID-19 cases, isolation rooms have become one of the most critical facilities in hospitals. Maintaining the correct temperature and humidity in these isolation rooms is a challenge, considering the heating, ventilation, and air conditioning (HVAC) systems that continuously consume large amounts of energy. With the application of energy conservation methods, the total energy consumption of HVAC systems can be reduced. Many studies have shown that the heat pipe heat exchanger (HPHE) technology can contribute significantly to energy savings using HVAC systems. In this study, the effectiveness of an HPHE on an HVAC system in an isolation room was examined, and the total energy reduction was quantified. The HPHE consisted of two rows with ten heat pipes in each row, arranged in a staggered configuration with fresh air temperature and mass flow variations. The inlet fresh air temperatures varied at 32, 35, 37, and 40 °C and fresh air velocities at 1.2, 1.6, 2.2, and 2.6 m/s. Using a chiller, the inlet fresh air was cooled to a comfortable temperature zone, approximately 24.4–25.2 °C, in the isolation room. Notably, higher velocities decreased the effectiveness of the HPHE. An increase in the flow rate enhanced the system, thereby improving the heat recovery value. The increase in the inlet fresh air temperature from 32 °C, that yielded an energy saving of 1.23 W, to 40 °C, resulted in a further energy saving of 1.85 W. The application of the HPHE in the HVAC system in isolation rooms represents a significant innovation that contributes to a reduction in total energy consumption.

A model-based evaluation of farmers' income variability under climate change (case study: autumn crops in Iran).

The study strives to analyze the potential variations of farmers' income under climate change by using Ricardian approach. The case study was Mazandaran province of Iran and three autumn crops, i.e. wheat, barley and canola were considered as the investigated crops. The Long Ashton Research Station Weather Generator (LARS-WG) model was selected to downscale the climate data. Three climate variables were downscaled for the years 2020-2080 under three climate scenarios: optimistic (RCP2.6), medium (RCP4.5), and pessimistic (RCP8.5). The Ricardian approach was also employed to predict the economics of climate change. Accordingly, the mean monthly temperature of the province is projected to have an upward trend under all climate scenarios, however, the rainfall pattern would be varied. The results of economic impacts of climate change also approved that the net income of investigated crops would be different trends under climate change scenarios. Accordingly, the variations of air temperature and rainfall would lead that the net income increases for wheat and barley, while it decreases for canola.

Comparing Atmospheric Temperature Fluctuations Across Landed Missions

AbstractWe analyze and compare atmospheric temperature data from three landed missions: Mars Science Laboratory (MSL) Curiosity rover, Phoenix lander, and Pathfinder lander. Pathfinder and Phoenix were lander missions that operated for 84 and 151 sols, respectively. MSL Curiosity is a rover that operates on the surface of Mars. It has recorded air temperature for more than five Mars Years (MY). We denoise and detrend temperature data from each mission and use those results to calculate variance in air temperature as a diagnostic for atmospheric variability at the surface. The results show a consistent seasonal pattern in MSL air temperature variance with little interannual variability outside major dust storms. The global dust storm in MY 34 was accompanied by a decrease in temperature variance and a muted response in peak MY 35 variance the following year. Phoenix (68°N, 2 m measurement height) and Pathfinder (19.7°N, 1.1 m measurement height) air temperatures have larger variance than air temperature from environmental data records at the MSL location (5.4°S, 1.6 m measurement height) at its equatorial latitude. Pathfinder variances per sol are larger than those of Phoenix, possibly due to a combination of Pathfinder's lower albedo surface and lower latitude. This occurs despite the Pathfinder location's higher thermal inertia, which would act to decrease noontime variance relative to a lower thermal inertia surface. Comparison of MSL temperature variance to pressure drops related to convective vortex activity shows consistent seasonal patterns; however, pressure drops tend to increase with increasing rover elevation, while variance remains consistent.

Strong differences in microclimate among the habitats of a forest-steppe ecosystem

Microclimate has a substantial impact on plant composition, survival, and growth, as well as ecosystem processes. Although microclimatic conditions in anthropogenically fragmented ecosystems have received considerable scientific attention, they are understudied in naturally fragmented ecosystems, including forest-steppes. In addition, earlier investigations in these mosaics only measured microclimate parameters for a very short period (i.e., 24 hours on a single summer day). In the present study, the long-term microclimatic conditions were described in multiple habitat types, both woody and non-woody, in a sandy forest-steppe ecosystem in the Kiskunság, central Hungary. The aim of this study was to answer (1) how air humidity and temperature conditions differ among the studied habitats during the growing season and (2) which habitats are more stressed to vegetation growth regarding vapor pressure deficit (VPD). Wireless sensors recording air temperature and humidity values were used to monitor microclimatic parameters. VPD values were calculated based on the obtained air temperature and humidity, and two thresholds at 1.2 and 3.0 kPa were defined. To compare mean air temperature and humidity variables, as well as above-threshold VPD rate among habitat types, general linear models were used. Our results indicated that open grasslands were the warmest and driest habitats. Among woody habitats, south-facing edges had the harshest microclimatic conditions. The current work also found that small forest patches and larger forest patches had similar air temperature and humidity variables. Regarding VPD, open grasslands were the most stressed for vegetation growth from May to October. During the summer season, forest patches had a small moderating effect at the limiting threshold of 1.2 kPa VPD, but a stronger moderating effect at the 3.0 kPa threshold. With ongoing climate change, this role of forest patches is expected to become increasingly important in forest-steppes. Therefore, it is suggested that the remaining near-natural forest stands in sandy forest-grassland ecosystems should be prioritized for protection, and that scattered trees or groups of trees of native species should be established in extensive treeless grasslands.

Trend and Variations of Surface Air Temperatures across Selected Eco-Climatic Zones in Nigeria

The trends and variability in surface air temperatures over selected eco-climatic zones in Nigeria were assessed using Merra-2 datasets from 1981 to 2018. A total of 15 stations spread across the eco-climatic zones in Nigeria were used for this study. The Mann-Kendall, linear trend and Sen’s slope trend test, time series plots and descriptive statistics were used. The coefficients of variability of surface air maximum temperature showed low variability for the Mangrove-swamp rainforest and moderate variability for the Guinea-wooded, Sudan and Sahel savannas. Similarly, the coefficients of variability of surface air minimum temperature showed moderate variability for all the selected eco-climatic zones. The M-K trend test showed that 14 stations had upward trends and 1 downward trend, with 13 stations having statistically significant trend in air surface maximum temperature. All the stations had statistically significant upward trends in air surface minimum temperature. The average increase in maximum and minimum air surface temperatures is estimated to be about 0.035°C and 0.036°C per year, respectively. For Nigeria, the average air surface temperature is estimated to increase by about 0.036°C per year, and the average air surface temperature is estimated to have increased by about 1.4°C over the 38 years. This study then gives a linear trend projection of about 4.3°C increase in estimated mean air surface temperature by year 2100 in Nigeria.

Quantitative assessment of summer air-temperature extremes in the high-altitude mountainous region of the Romanian Carpathians during the period 1990-2020

Based on the daily summertime air temperature observations available during the 1990-2020 period, this study makes a quantitative analysis of the annual and monthly variations of daily maximum air temperatures and of some relevant heat indices as defined by the ETCCDI (indices of extremes and climate change) set, at eight meteorological stations (Bâlea Lac, Ceahlau Toaca, Iezer, Lacau?i, Parâng, Omu Mnt. and Vladeasa 1800) located above 1,500 m in the Romanian Carpathians. During the reference period, the maximum air-temperatures exceed 20°C at all eight meteorological stations analyzed, with altitude and local topography playing a very important role. In general, air temperatures in Romania are continuously increasing, the warming signal being given by various factors, as was also observed at the analyzed meteorological stations, with higher air- temperatures at the Parâng meteorological station and lower air-temperatures on the Omu Mount. The results of this study reveal the followings: 1) the warming process is ongoing and intensifying in the mountainous area; 2) high air temperature values were recorded at all analyzed stations, especially at Parâng station, exceeding 25°C (in 50 days of the reference period). The highest values of the analyzed temperature indices in the entire period 1990-2020 were recorded at Parâng mountain meteorological station, while the lowest ones were recorded on the Omu Mount. The year 2012 was the warmest year of the analyzed period.

ГИДРОМЕТЕОРОЛОГИЧЕСКИЕ ФАКТОРЫ И ИХ ВЛИЯНИЕ НА СОДЕРЖАНИЕ ХЛОРОФИЛЛА-α В АЗОВСКОМ МОРЕ В 2006–2022 ГГ.

Background. Chlorophyll-α concentration is a key environmental parameter used to calculate the primary production of a water body, which, in turn, determines phytoplankton biomass. The fields with increased chlorophyll concentration can develop under the influence of various hydrometeorological factors considered in this work, such as air and water temperatures, cloud amount, wind-driven water mixing, and precipitation affecting the surface water layer. Relevance. Monitoring of chlorophyll distribution as it is influenced by hydrometeorological factors facilitates the rational fisheries management on account of their relation to the phytoplankton biomass providing fish and zooplankton with a food source. The aim of this work is to analyze the inter-annual variability of the average monthly hydrometeorological factors and their influence on the chlorophyll-α concentration in the Azov Sea (excluding Taganrog Bay) for the time range from 2006 to 2022. Methods. Spatial and temporal analysis of the average monthly water temperatures and chlorophyll-α concentrations has been conducted based on the daily satellite images of the sea surface taken by MODIS spectroradiometer in the Azov Sea; the analysis of the meteorological characteristics has been carried out using the weather observation data from international data exchange and reports (SYNOP, METAR) posted on the website pogodaiklimat.ru for the time range from April 2006 to September 2022. Results. It is shown that, for the entire investigated time range (2006–2022), the trends of the inter-annual variability of the average monthly air and water temperatures were not significant. An increase in water temperature that started in the middle of 1990s changed for the opposite in 2011, i. e. turned into a decrease. The wind velocity above the Azov Sea (excluding Taganrog Bay) over the investigated time range gradually decreased, which fell in line with the decrease in the chlorophyll-α concentrations. The average monthly cloud amount in the area has shown a weak inter- annual and considerable seasonal variability with relatively low values in the summer season and high values in the winter season. A positive trend of the monthly amount of atmospheric precipitation was observed, in contrast with the negative trend of the chlorophyll-α concentration. Conclusion. A significant positive correlation of the average monthly chlorophyll-α values with water and air temperatures has been identified, as well as a negative one with the wind velocity and cloud amount over the Azov Sea (excluding Taganrog Bay) — both in the individual investigated areas and in the sea as a whole.

Investigation of the performance of cold-end system in direct air-cooled power units under the influence of ambient winds

Direct air-cooled condensers in power plants rely on heat transfer with the atmospheric environment to discharge thermal energy. The heat transfer process becomes complicated in practical operations when ambient wind is involved. To examine the impact of wind on the heat transfer performance of direct air-cooled condensers, this paper took into consideration three different wind directions, namely, headwind, crosswind and tailwind, as well as four different speeds (3 m/s, 6 m/s, 9 m/s, and 12 m/s), and numerically investigated their influences on the thermal performance of a 600 MW direct air-cooled power unit. The variation in ventilation rates and inlet air temperatures among the cells under the influence of ambient winds are also studied. Simulation results indicated that ambient winds induced thermal air re-circulation and air backflow phenomena in the air-cooled island. The cells located on the windward side were significantly affected in all three wind direction conditions. The ventilation rates and inlet air temperatures among the cells were not uniform, showing an overall increasing trend. In particular, negative pressure zones were generated under tailwind conditions, severely impacting air-flow rates at the fan inlet, and inlet air temperatures of cells. These phenomena became more pronounced with increasing wind speeds.

Thin‐Layer Drying Model, Drying Rate, and Effective Water Diffusion Coefficient of Pelleted Feed

In this study, classic thin‐layer drying models such as the Page model, Verma model, and Two‐term model were used to fit the thin‐layer drying data of feed. Based on this, a novel thin‐layer drying model for pelleted feed (modified Verma model) was proposed. The results indicate that the new model is the optimal choice for describing the drying kinetics of pelleted feed for growing pig and calf. The drying rate of pelleted feed is linearly correlated with the feed moisture content. The effective water diffusion coefficient for pelleted feed of growing pig and calf ranges from 1.86 × 10−10 to 2.75 × 10−9 m2/s and 3.32 × 10−10 to 3.87 × 10−9 m2/s, respectively. The activation energy (Ea) for moisture diffusion in both types of feed is 26.42 kJ/mol and 25.86 kJ/mol, respectively. By establishing predictive models for model parameters based on air temperature and air velocity variables, the new model demonstrates extrapolation capability, wide applicability, and practical value. This work lays the foundation for developing a similarly characterized deep‐bed cooling drying model for pelleted feed.

Calotropis procera (Apocynaceae) shrub intrusion on wildlife foraging rangelands in the Ruaha National Park

The relationships between the encroachment of Calotropis procera (Apocynaceae) and understorey herbaceous cover and various environmental variables of recipient grasslands were studied in the north-eastern Ruaha National Park in southern Tanzania. Three hypotheses were investigated. (1) C. procera exerts a negative influence on the cover of understorey herbaceous plants. (2) C. procera exerts a negative influence on environmental variables (humidity, light intensity, soil pH, air temperature, and soil temperature). (3) The native shrub canopy exerts a negative influence on understorey herbaceous plant cover and the environmental variables. We identified two sampling areas, one encroached by C. procera, the other with only native tree/shrub species. In each area, 21 5 m × 5 m subplots were established, and within each, two 1 m × 1 m sample plots were established, one 20 cm from the stem of a C. procera or native trees/shrub, the other at 5 m distance, and herbaceous plant cover and environmental variables were measured. Variables were measured on three occasions (December 2022, March, and July 2023) on the 42 subplots in each sampling area. Results demonstrated a negative influence of C. procera on understorey herbaceous cover, with a significantly lower percentage (16 ± 1.7) of herbaceous cover for plots at 20 cm than 5 m (72.4 ± 1.4) from C. procera stems. Moreover, soil pH was significantly lower at 20 cm than at 5 m distance from the stems in the encroached area, whereas in the non-encroached area, there was no recorded difference in the environmental variables. These results emphasised the necessity for a prompt intervention to contain the spread of C. procera in suitable grazing areas. A detailed study to find out the most practical and cost-effective control approaches appears warranted.

Variability of climatic norms during instrumental observations in the Kuzbass Botanical Garden

In the work, based on a number of observations at station 29645 Kemerovo for the period from 1955 to 2023, the long-term variability of air temperature was investigated. For the first time for the Kuzbass Botanical Garden, climatic norms for the period 1991–2020 were estimated, using linear trend analysis, the rates of change in climatic indicators were estimated. It has been established that climatic indicator on the territory of the Kuzbass Botanical Garden for the period from 1955 to 2023. have an upward trend. However, the temperature growth rates are slightly higher than those noted for Western Siberia. It has been shown that the climatic standards of air temperature in the modern period differ significantly from the base period of 1961–1990 proposed by WMO.

Variability of climatic norms of annual precipitation in the Kuzbass botanical garden

In the work, based on a number of observations at station 29645 Kemerovo for the period from 1951 to 2023, the long-term variability of air temperature and precipitation was investigated. For the first time for the Kuzbass Botanical Garden, climatic norms for the period 1991–2020 were estimated, using linear trend analysis, the rates of change in climatic indicators were estimated. It has been established that climatic indicator on the territory of the Kuzbass Botanical Garden for the period 1951–2023. have an upward trend. However, the temperature growth rates are slightly lower than those noted for Western Siberia. Annual precipitation is characterized by stable growth throughout the study period. However, there is some instability of this trend. It has been shown that the climatic standards of air temperature and precipitation in the modern period differ significantly from the base period of 1961–1990 proposed by the WMO.

Comparison of Local Mean Age of Air between Displacement Ventilation System and Mixing Ventilation System in Office Heating Conditions during Winter

A novel displacement ventilation system (DVS) was designed using a four-way cassette fan coil unit (FCU) and air purifiers (APs) for supplying clean air. The proposed DVS in this study involved drawing indoor air through the FCU and diffusers installed in the ceiling, controlling air temperature using the FCU, and then discharging it back into the office through the APs placed on the floor. The comparative ventilation system considered was the typical mixing ventilation system (MVS) that intakes and exhausts indoor air using diffusers installed on the ceiling. The local mean age of air was used as an index to compare indoor air quality between DVS and MVS under winter heating conditions. It was found that the DVS was more effective in improving indoor air quality in winter than the MVS. Moreover, compared to the MVS, utilizing the DVS designed in this study resulted in the advantage of a much more uniform air temperature variation in the office space. Therefore, it is anticipated that modifying the structure of an indoor space with an FCU installed in the ceiling and APs on the floor to use the DVS designed in this study would greatly assist in enhancing indoor air quality.

Thermal characterization and ventilation assessment of a battery-caged laying hen housing in the humid tropic climate.

The indoor climate to which livestock are exposed is a critical factor influencing their performance and productivity. Elevated air temperature and relative humidity could result in heat stress for laying hens. This situation results in severe adverse effects such as weight loss and mortality. Egg fertility and hatchability are also impacted. Consequently, a study was carried out in a naturally ventilated battery-caged laying hen house to measure climatic variables (air temperature, relative humidity and air velocity). The degree of heat stress was assessed using the temperature-humidity index (THI), and the index of temperature and air velocity (ITV) was also evaluated. According to the results obtained, birds reared within the study building would spend most of their productive life under stressful thermal conditions, which could significantly hamper their performance. The air velocity was below 1.0 ms-1 for most of the internal part of the housing, meaning natural air movement at the location was insufficient to provide a suitable environment for the birds. A high THI was recorded for nearly the entire study period. This high THI could indicate high relative humidity about air temperature. The observed ITV values (ITV > 25) suggest that birds throughout the building could be perpetually uncomfortable. The thermal and velocity profile within the structure could further be assessed numerically using computational fluid dynamics. This would enable engineers to make modifications to improve living conditions within the building.

PRELIMINARY EVALUATIONS OF AIR TEMPERATURE EFFECTS ON THE RESPONSE OF SEISMICALLY ISOLATED BRIDGES EMPLOYING ELASTOMERIC BEARINGS

Laminated rubber bearing is a common seismic protection device for bridge structures based on its high vertical stiffness, low horizontal and rotational stiffness, and significant lateral restoring capacity. However, the mechanical behavior of elastomers, particularly the material's shear stiffness, is significantly influenced by variations in air temperature. The cyclic behavior of elastomeric isolators is affected by variations in air temperature and this is considered by current seismic codes through requiring upper and lower bound analysis using relevant modification factors. As a result, it significantly impacts the seismic responses of structures employing laminate rubber isolators. However, this aspect is not frequently considered when designing seismic isolation in most locations. This article aims to evaluate the effect of air temperature on the seismic response of isolated bridges. A parametric study, with varying temperature conduction, is carried out. The responses of a seismically isolated bridge are evaluated by the peak value of lateral force and displacement. Results indicate that air temperature has considerable effects on the behavior of rubber isolators and seismic responses of isolated bridges.

Interannual variability of ice cover across Davis Strait and the Labrador Sea for the period from 1979 to 2023

In conditions of rapid development of trade and transport communications, the issue of navigation through ice regime zones became of greater importance. In particular, reduction of the area of ice cover in the Canadian Arctic because of global warming opens up favourable prospects for further development of maritime shipping in this zone. Considering that the routes through the Northwest Passage are the shortest ones of all the routes connecting the Atlantic and Pacific oceans, it is clear that all aspects of this topic are of great importance and relevance. This especially applies to the aspects dedicated to studying the characteristics of appearance, formation, concentration, physical characteristics, trajectory of ice movement and forecasting the area of the ice cover in a given zone, i.e. the characteristics affecting the conditions of ice navigation and serving as determining factors in terms of navigation safety.
 The research examines some of these issues, namely the spread of the ice cover during the period of its maximum formation across Davis Strait and the Labrador Sea (where the routes through the Northwest Passage start) and the establishment of statistical relations between the ice spread and the temperatures of surface water and surface air. The research method to be used: synoptic-climatic and statistical analysis of numerical series of ice cover deviations from its average limit as of April 15 over the period of 1979-2023 within the zone in study.
 Based on the set goal, the study processed raw data on distribution of ice cover across Davis Strait and the Labrador Sea for the period of 1979-2023 and completed its statistical analysis. The results of the analysis showed presence of a statistically significant negative trend and cyclical fluctuations with periods of 3-6, 9, 10 and 13 years in relation to the interannual variability of ice cover distribution for the studied period. Positive trends are also observed in the interannual variability of surface water temperature and surface air temperature. After bringing the original series to a quasi-stationary form, a correlation analysis of the relationships between the ice cover distribution and the temperature of water and air was carried out. The results of the analysis determined zones and points with statistically significant correlation coefficients between them during the year. It turned out that the highest values of coefficients are observed from December to March, and the maximum one occurs in March.
 Systematization and analysis of the ice field across Davis Strait and the Labrador Sea during the period of maximum development made it possible to establish that the spread of ice between 60° and 55° north parallels was the most stable during the studied period, and the least stable was observed in the area below 55° north parallel.
 The results of the conducted research open up prospects for development of methods for forecasting the distribution of ice cover across Davis Strait and the Labrador Sea. This will make ice navigation in this area safer.

Mountain Taiga in a Warming Climate: Contrast of Siberian Pine Growth along an Elevation Gradient

The growth and survival of trees in the Siberian Mountains are experiencing a strong influence on climate warming. We analyzed Siberian pine (SP, Pinus sibirica) growth within the treeline ecotone in high (>1000 m) and low (<900 m) lands. We used ground surveys, dendrochronology, and climate variable data analysis. We found a contrasting response of SP growth with increasing air temperature and moisture parameters along the elevation gradient. In the treeline ecotone and highlands, the tree’s growth has been increasing since warming onset in the 1970s, whereas in the lowlands, the initial growth increase switched to a growth drop since the beginning of the 2000s, with a consequent partial mortality of the Siberian pine forest caused by warming-driven water stress in combination with bark borers’ attacks. This mortality suggests the retraction of the Siberian pine range in the lowlands of the Siberian Mountains. The projected drought increase will likely lead to the substitution of Siberian pine with drought-tolerant species. The tree’s growth index (GI) dependence on air temperature and moisture variables includes two phases. In the first phase (since the warming onset in the 1970s), the trees’ GI was positively correlated with elevated temperature, whereas correlations with precipitation and soil moisture were negative. During the second phase (since the increase in warming in the 2000s), negative correlations between the GI and moisture variables switched to positive ones. The correlations of the GI with air temperature switched from positive to mostly insignificant. The wind’s influence on the trees’ growth changed from negative to insignificant since the 2000s within all elevation belts. Afforestation within the areas of Siberian pine mortality should not be based on the planting of Siberian pine but on drought-tolerant species such as larch (Larix sibirica) and Scots pine (Pinus sylvestris).

Temporal Variability of Soil Temperature in the North-West Arctic Zone of Russia. Part I: Interannual Linear Trends Based on Thermometer Measurements and Reanalysis Data

In this article we investigate near-surface air temperature (NSAT) and soil temperature variability at four depths in the region of the White Sea, Murmansk and Arkhangelsk Regions, and Republic of Karelia. For the analysis we used NOAA-CIRES-DOE 20th Century Reanalysis (Version 3) reanalysis data for the 1980–2015 time period and data of bent-stem thermometers at 5, 10, 15, 20 cm depths and extraction thermometers at 20, 60, 80, 120, 240 and 320 cm depths for 1985-2021 time period. Average variability of NSAT is estimated using linear trend as +0.028 ◦C/year. For soil temperature a linear trend is of +0.0137 ◦C/year on surface (0 cm), +0.0136 ◦C/year at 10 cm depth, +0.0142 ◦C/year at 40 cm depth and +0.0133 ◦C/year at 100 cm depth.

Changes in the parameters of extreme temperature events in the western part of the Russian Arctic according to ERA5 and MERRA-2 reanalyses in 1980–2022

The air temperature in the Arctic zone of Russia is increasing at a rate of 0.71 °C per decade, which is three times faster than the global average. The warming of climate is accompanied by an increase in its extremeness, which leads to an increase in the number of dangerous hydrometeorological phenomena. The most significant changes occurred in the statistics of large-scale summer heat waves in European Russia. One of the most important goals in studying current climate changes is to study the frequency of extreme hydrometeorological phenomena, in particular, heat or cold waves. In this paper, we investigate the average daily anomalies relative to the annual variation of air temperature at a height of 2 meters from the surface in the region of the western part of the Russian Arctic (60°–75° N, 30°–85° E), according to ERA5 and MERRA-2 atmospheric reanalyses for the period 1980–2022. Their root-mean-square deviations and the distribution of their average number per year are calculated. We have plotted the fields of average values and the rate of changes in the amplitude, duration and number of anomalous temperature events which exceed two standard deviations in the study region. Areas of increase and decrease in the amplitude, duration and number of extreme events, both with positive and negative temperature anomalies, are displayed. In general, it can be concluded that, on average, the amplitudes of positive extreme air temperature anomalies in the study area slightly increase. The duration of positive extreme anomalies is growing everywhere at a rate of 0.2 days per 10 years. The duration of negative extreme anomalies slightly decreases. The number of events with negative extreme anomalies has been decreasing at a rate of –0.5 to –3 events per year for 10 years, while the number of events with positive extreme anomalies has been increasing from 0.1 to 1 events per year for 10 years.The results obtained significantly expand our knowledge of the spatiotemporal features of the ongoing changes in the extreme climate of the western part of the Russian Arctic, which is of paramount importance for the analysis and forecasting of the development of natural and socio-economic systems in the region under study.

Enhanced Subseasonal Variability of Spring Temperature Over Eastern China in 2022: Initial Role of Extremely Heavy Arctic Sea Ice in Previous Winter

AbstractIn spring 2022, strong temperature whiplash events occurred in eastern China (EC), characterized by enhanced subseasonal variability in surface air temperature (SAT). Our results show that extreme temperature fluctuations are dominated by the amplified Eurasian wave train on a biweekly timescale as a possible response to increased sea ice concentrations (SICs) over the Barents‐Kara Seas (BK) in previous winter. Increased winter SICs weaken the upward planetary waves and enhance the stratospheric polar vortex. In spring, the downward propagation of enhanced polar vortex intensifies the polar front jet, increasing kinetic energy gain of the North Atlantic wave train and guiding it to travel farther eastward. The Eurasian wave train strengthens through an upstream development and enhanced local baroclinicity and enhances subseasonal SAT variability over EC. Therefore, the state of BK SICs in previous winter could be a useful signal for the enhanced likelihood of spring extreme temperature whiplash events.