Daily Temperature Changes Research Articles

The Impact of Meteorological Factors on Stroke Incidence in the Transdanubian Region of Hungary

Cerebrovascular diseases are the leading cause of death and disability. The epidemiological background and predisposing factors have been the basis of many studies. We aimed to assess the effect of seasonal variability and meteorological factors on stroke incidence in Hungary. National and county-level secondary data were assessed for 2018–2019. We identified stroke with ICD codes I60, I61, I62 (hemorrhagic), I63, I65, and I66 (ischemic). The data were obtained from the University of Pécs Clinical Centre (number of patients per day according to sex and disease subtype, n = 1765). Daily average and maximum wind speed [m/s], precipitation [mm], temperature [°C], and frontal effect [warm/cold/mixed/no effect]) were provided by the Hungarian Meteorological Service. We found that 89.92% of the patients were hospitalized for ischemic and 10.08% for hemorrhagic stroke. We observed a significantly higher number of cases in the other months compared to winter (spring: +35.9%; p = 0.007, summer: +59.0%; p = 0.016, autumn: +36.5%; p = 0.01). In autumn, an increase in temperature increased the incidence of stroke (r = 0.210; p = 0.004). Temperature change affected ischemic stroke incidence (r = 0.112; p = 0.003). In contrast, the number of hemorrhagic stroke cases showed a mild but significant negative association with daily temperature change (r = −0.073; p = 0.049). Overall, a 1 °C temperature change compared to the previous day increased the daily number of admissions by 2.9% (p = 0.017). Air pressure change also affected hemorrhagic stroke incidence (r = 0.083; p = 0.025). Changes in temperature and frontal effects can increase the incidence of stroke. Modern forecasting technology can help the healthcare system prepare for possible increased workloads during critical periods.

The relationship of short-term exposure to meteorological factors on diabetes mellitus mortality risk in Hefei, China: a time series analysis.

The study aims to explore whether short-term exposure to meteorological factors has a potential association with the risk of diabetes mellitus (DM) mortality. During the period 2015-2018, we collected daily data on meteorological factors and deaths of diabetic patients in Hefei. A total of 1101 diabetic deaths were recorded. We used structural equation modeling to initially explore the relationships among air pollutants, meteorological variables, and mortality, and generalized additive modeling (GAM) and distributional lag nonlinear modeling (DLNM) to explore the relationship between meteorological factors and the mortality risk of DM patients. We also stratified by age and gender. The mortality risk in diabetic patients was expressed by relative risks (RR) and 95% confidence intervals (CI) for both single and cumulative days. Single-day lagged results showed a high relative humidity (RH) (75th percentile, 83.71%), a fairly high average temperature (T mean) (95th percentile, 30.32°C), and an extremely low diurnal temperature range (DTR) (5th percentile, 3.13°C) were positively related to the mortality risk of DM. Stratified results showed that high and very high levels of T mean were significantly positively linked to the mortality risk of DM among females and the elderly, while very high levels of DTR were linked to the mortality risk in men and younger populations. In conclusion, this study found that short-duration exposure to quite high T mean, high RH, and very low DTR were significantly positively related to the mortality risk of DM patients. For women and older individuals, exposure to high and very high T mean environments should be minimized. Men and young adults should be aware of daily temperature changes.

The Hypogeous Roman Archeological Museum of Positano: Study of the Evolution of Biological Threaten and Development of Adequate Control Protocols.

Hypogea are natural or artificial spaces located underground often of great interest from an anthropological, archeological, religious, artistic, or historic point of view. Due to their features, these environments usually present conservative problems and biological colonization could be considered as one of the main threats. The present three-year study was carried out by specialists of the Central Institute for Restoration of Rome (ICR) in the hypogeous site preserved in the Roman Archeological Museum of Positano (Positano MAR) and focused on characterizing biological alterations present on the mural paintings; setting up efficient strategies and protocols for biodeterioration control; and monitoring the efficacy of direct and indirect interventions. Patinas with different morphologies were analyzed through microscopic observations, cultural analyses and next-generation sequencing. The results proved that the alterations comprised a great variety of microorganisms forming very distinct communities, differently distributed over space and time. The main taxa represented were bacteria of phyla Pseudomonadota and Actinomycetota, fungi belonging to the genus Fusarium and Gliocladium, and algae of the genus Chlorococcum. Preservation protocols were set up considering the alterations' composition and included the application of biocides, limiting daily temperature changes, decreasing illuminance values on painted surfaces, and the screening of natural light sources.

Numerical modeling of microclimate of re-waterlogged lands of Belarusian Polesie

Based on the mesoscale hydrodynamic model WRF (Weather Research and Forecasting), the balance model of atmospheric moisture and the remote sensing data, we obtained the estimates of microclimate changes as a result of reswamping of lands in Belarusian Polesie. The calculations were performed on the example of the Khoiniki district of the Gomel region of Belarus. Numerical experiments considered the driest summer periods of the last two decades. Based on the modeling results, the maps of changes in mean daily temperature, amplitude of daily temperature variations, evapotranspiration and precipitation were constructed, which can be used to predict the consequences of land reclamation in different scenarios of adaptation to climate changes.

Study of the Strain Law and Model of an Open-Air Steel Column under Daily Temperature Changes in Winter

Steel structures with light weight, high rigidity, and easy assembly have become the first choice for large-span complex building materials. At the same time, transparent materials are widely used for the sake of practicality and aesthetics. However, steel structures will be deformed due to changes in temperature, which will affect the accuracy of closure. The components are restricted from free deformation as a result of multiple statically indeterminate structures. A safety hazard will occur if the residual temperature stress is not released. At present, the strain law of open-air steel structures caused by temperature change is still unclear, and the corresponding temperature–strain model has not been established. This paper is based on the third-phase reconstruction and expansion project of Taiyuan Wusu Airport in Xiaodian District, Taiyuan City, Shanxi Province (37°45′ N, 112°38′ E, average altitude of 774 m), winter long time series temperature measured data, deduced daily temperature change laws, and the established relationship model between air temperature and steel surface temperature. Based on the measured data of long-term stress and strain in winter, the strain law of open-air steel columns under temperature change is discussed. According to the results, the air temperature can be utilized to determine the strain of the open-air steel column during winter. The determination coefficient of the temperature–stress model can reach 0.868, and the radial bending stress caused by the change in daily temperature cannot be ignored, accounting for 15.7% of the radial stress at the same time, which can provide a reference for stress calculations of similar structures.

Investigating the impact of weather on stroke in summer.

The objective of this study is to explore how changes in weather contribute to an increase in hospital admissions for stroke in summer. We collected 96,509 cases of stroke hospitalization data in Tianjin from 2016 to 2022 summer, along with corresponding meteorological data. The generalized additive model and distributed lag nonlinear model were used to analyze the lag and cumulative effects of temperature on stroke hospitalization. The research results show both the cold effect and the heat effect in summer would increase the risk of hospitalization. The effect of daily maximum temperature on stroke hospitalization was immediate when the temperature was higher, and delayed when the temperature was lower. However, the risk of stroke hospitalization increased more significantly with increasing temperature than with decreasing temperature. In the presence of one or more of the following three weather changes: sharp temperature increase, sharp temperature decrease, continuous high temperature, the daily number of stroke inpatients were higher than the average in the same period. 83% of the Inpatient-heavy events within the study period were caused by a combination of dramatic temperature changes and continuous high temperatures. In 48% of Inpatient-heavy events, continuous high temperature weather above 30℃ for at least 4 consecutive days were observed. And 55% of high temperature weather was accompanied by high humidity. When the daily relative humidity was greater than 70% and the daily maximum temperature was between 26 and 28℃ or more than 34℃, or the daily maximum temperature changes over 10℃ within 48h, the number of daily inpatients was more than 1.2 times of the average daily inpatients. More attention should be paid to the combined effects of continuous high temperature and sudden temperature changes in summer stroke prevention.

Soil-structure interaction issues in integral abutment bridges

Integral Abutment Bridges (IABs) are constructed without expansion joints and bearings, connecting the bridge deck monolithically to the end abutments. Therefore, the construction and maintenance costs of IABs are low compared to conventional bridges with bearings and joints. However, the soil-structure interaction issues are more complex for IABs due to the transfer of deck movements to the foundations through the abutments. Hence abutments of these bridges play an important role in the performance of the substructure and consequently the design approach for the substructure. In this paper, soil-structure interaction issues are investigated for the deck movements due to cyclic thermal loading, which occurs as a combination of daily and seasonal temperature changes. The development of a physical model facility to simulate the problem is described with scaling laws and material properties. The settlement problem at the bridge approach and stress ratcheting phenomena observed at the abutment soil interface are discussed using results from model tests. For the prediction of lateral earth pressure distribution behind abutments, currently available methods are discussed, and modifications are proposed. Finally, the effectiveness of Expanded Polystyrene (EPS) geofoam as an inclusion is discussed to mitigate approach settlement and stress ratcheting problems due to cyclic thermal loading. The results of this study confirm that EPS geofoam is a highly effective material to minimise adverse soil-structure interaction issues in integral bridge abutments.

Future projections of temperature-related indices in Prince Edward Island using ensemble average of three CMIP6 models

Prince Edward Island (PEI) is an agricultural province heavily relying on rainfed agriculture. The island has already experienced significant impacts from climate change. Accurate projections of PEI temperature extreme indices are required to mitigate and adapt to the changing climate conditions. This study aims to develop ensemble projections using Coupled Model Intercomparison Project Phase 6 (CMIP6) global circulation models (GCMs) to analyze temperature extremes on PEI. In this study, the ECMWF ERA5 reanalysis dataset was chosen for stepwise cluster analysis (SCA) due to its high accuracy. Three CMIP6 (NorESM2-MM, MPI-ESM1.2-HR, and CanESM5) GCMs, along with their ensemble average, were utilized in the SCA model to project future changes in daily maximum temperature (Tmax) and minimum temperature (Tmin) at four meteorological stations on PEI (East Point, Charlottetown, Summerside, and North Cape) under two shared socioeconomic pathways (SSP2-4.5 and SSP5-8.5). These GCMs were selected based on their low, medium, and high Equilibrium Climate Sensitivity. The bias-corrected results for the future period of Tmax and Tmin showed that the GCM-specific changes in the ECS also impact the regional scale. Additionally, several temperature extreme indices, including the daily temperature range (DTR), summer days (SU), growing degree days (GDD), growing season length (GSL), ice days (ID), and frost days (FD), were analyzed for two future periods: FP1(202–2050) and FP2 (2051–2075). The results indicate that DTR, SU, GDD, and GSL are expected to increase, while ID and FD are projected to decrease during FP1 and FP2 under both scenarios. The future projected mean monthly changes in Tmax, Tmin, and the selected temperature extreme indices highlight warmer future periods and an increase in agriculture-related indices such as GDD and GSL. Specifically, July, August, and September are expected to experience even higher temperatures in the future. As the climate becomes warmer, cold extreme events are projected to be shorter in duration but more intense in terms of their impact. The largest increments/decrements for Tmax, Tmin, and their relevant indices were observed during FP2 under SSP5-8.5. The outcomes of this study provide valuable insights for agricultural development, water resource management, and the formulation of effective mitigation strategies to address the impacts of climate change on PEI.

Feeding behavior modifies the circadian variation in RR and QT intervals by distinct mechanisms in mice.

Rhythmic feeding behavior is critical for regulating phase and amplitude in the ≈24-h variation of heart rate (RR intervals), ventricular repolarization (QT intervals), and core body temperature in mice. We hypothesized changes in cardiac electrophysiology associated with feeding behavior were secondary to changes in core body temperature. Telemetry was used to record electrocardiograms and core body temperature in mice during ad libitum-fed conditions and after inverting normal feeding behavior by restricting food access to the light cycle. Light cycle-restricted feeding modified the phase and amplitude of 24-h rhythms in RR and QT intervals, and core body temperature to realign with the new feeding time. Changes in core body temperature alone could not account for changes in phase and amplitude in the ≈24-h variation of the RR intervals. Heart rate variability analysis and inhibiting β-adrenergic and muscarinic receptors suggested that changes in the phase and amplitude of 24-h rhythms in RR intervals were secondary to changes in autonomic signaling. In contrast, changes in QT intervals closely mirrored changes in core body temperature. Studies at thermoneutrality confirmed that the daily variation in QT interval, but not RR interval, primarily reflected daily changes in core body temperature (even in ad libitum-fed conditions). Correcting the QT interval for differences in core body temperature helped unmask QT interval prolongation after starting light cycle-restricted feeding and in a mouse model of long QT syndrome. We conclude feeding behavior alters autonomic signaling and core body temperature to regulate phase and amplitude in RR and QT intervals, respectively.NEW & NOTEWORTHY We used time-restricted feeding and thermoneutrality to demonstrate that different mechanisms regulate the 24-h rhythms in heart rate and ventricular repolarization. The daily rhythm in heart rate reflects changes in autonomic input, whereas daily rhythms in ventricular repolarization reflect changes in core body temperature. This novel finding has major implications for understanding 24-h rhythms in mouse cardiac electrophysiology, arrhythmia susceptibility in transgenic mouse models, and interpretability of cardiac electrophysiological data acquired in thermoneutrality.

Impact of Temperature and Atmospheric Pressure on Hospitalizations of Patients Presenting With Acute Coronary Syndrome.

This study aims to investigatethe impact of temperature and atmospheric pressure on hospitalizations of patients with acute coronary syndrome (ACS). This is a retrospective, observational, analytical study conducted in a single center, University Hospital Center "Mother Teresa," Tirana, Albania, in the period January-December 2018. This study included 1,165 patients with ACS, who performed urgent coronary angiography, from January 2018 to December 2018. Patients were diagnosed withACS based on clinical and examination findings. The data were collected retrospectively using patient files. Baseline demographic, clinical, and procedural characteristics were collected. Data on atmospheric parameters, measured at the weather monitoring station, were obtained from the National Meteorological Service database. Measurements from the meteorological service provided values ​​for each parameter: average daily temperature and atmospheric pressure in each country district. Atmospheric data measurements were taken for the day under review. The number of inhabitants for the respective districts is taken from the National Institute of Statistics (INSTAT). The study involved 1,165 patients, with a mean age of 63.1 years, ranging from 27 years to 89 years old. The majority of patients (78.6%) were male, while 21.4% were female. A statistically significant relationship was observed between seasonal changes in temperature and atmospheric pressure concerning the number of cases with ACS; the autumn season prevails with 27.9% of the total cases, followed by the spring season with 25.6%, the summer season with 24.2%, and winter season with 22.3% (p = 0.04). Additionally, significant changes in the average monthly values ​​of temperature and atmospheric pressure were accompanied by a statistically significant increase in the number of cases as occurred in March-April and October-November (p ≤ 0.05). Most cases in the cold period (November-March) occurred on days with a change in temperature or atmospheric pressure with a statistically significant value of p < 0.05. An important relationship between seasonal, monthly, and daily changes in temperature and atmospheric pressure concerning the frequency of cases with ACS was observed.

Effect of Ambient Temperature on Impedance-Based Physiological Activity Evaluation of Zelkova Tree

A system has been developed to remotely, continuously, and quantitatively measure the physiological activity of trees. The developed tree physiological activity monitoring (TPAM) system is equipped with electrical impedance, temperature, and light intensity measurement functions. In the two-contact impedance measurement method used in the previous plant impedance measurement, errors due to the polarization impedance of the electrodes could not be avoided. The developed TPAM system adopted a four-contact measurement method that could avoid polarization impedance errors, and, with it, the long-term monitoring of zelkova trees was performed. The monitoring of seasonal changes was conducted from July to November, and an impedance change pattern that repeated on a daily basis was observed in the short term, and an overall increase in the impedance was observed in the long term. Impedance changes related to daily temperature changes were observed even after all the tree leaves had fallen, meaning that this effect should be excluded when using impedance to evaluate tree vitality. For this reason, the influence of temperature fluctuations was excluded by using only the impedance values at the same daily temperature of 25 degrees from July to November. The analysis results at 25 degrees showed that the tree impedance value increased linearly by 8.7 Ω per day. The results of this series of long-term monitoring and analysis revealed that the ambient temperature must be taken into account in the evaluation of tree physiological activity based on electrical impedance.

Rapid weather changes are associated with daily hospital visitors for atrial fibrillation accompanied by abnormal ECG repolarization: a case-crossover study

BackgroundAtrial fibrillation (AF) is highly prevalent in the population, yet the factors contributing to AF events in susceptible individuals remain partially understood. The potential relationship between meteorological factors and AF, particularly with abnormal electrocardiograph (ECG) repolarization, has not been adequately studied. This case-crossover study aims to investigate the association between meteorological factors and daily hospital visits for AF with abnormal ECG repolarization in Shanghai, China.MethodsThe study cohort comprised 10,325 patients with ECG-confirmed AF who sought treatment at Shanghai Sixth People's Hospital between 2015 and 2018. Meteorological and air pollutant concentration data were matched with the patient records. Using a case-crossover design, we analyzed the association between meteorological factors and the daily count of hospital visitors for AF with abnormal ECG repolarization at our AF center. Lag analysis models were applied to examine the temporal relationship between meteorological factors and AF events.ResultsThe analysis revealed statistically significant associations between AF occurrence and specific meteorological factors. AF events were significantly associated with average atmospheric pressure (lag 0 day, OR 0.9901, 95% CI 0.9825–0.9977, P < 0.05), average temperature (lag 1 day, OR 0.9890, 95% CI 0.9789–0.9992, P < 0.05), daily pressure range (lag 7 days, OR 1.0195, 95% CI 1.0079–1.0312, P < 0.01), and daily temperature range (lag 5 days, OR 1.0208, 95% CI 1.0087–1.0331, P < 0.01). Moreover, a significant correlation was observed between daily pressure range and daily temperature range with AF patients, particularly those with abnormal ECG repolarization, as evident in the case-crossover analysis.ConclusionThis study highlights a significant correlation between meteorological factors and daily hospital visits for AF accompanied by abnormal ECG repolarization in Shanghai, China. In addition, AF patients with abnormal ECG repolarization were found to be more vulnerable to rapid daily changes in pressure and temperature compared to AF patients without such repolarization abnormalities.

Robust Responses of Female Caribou to Changes in Food Supply.

AbstractUngulates can respond to changes in food supply by altering foraging behavior, digestive function, and metabolism. A multifaceted response to an environmental change is considered robust. Short seasons of plant growth make herbivores sensitive to changes in food supply because maintenance and production must be accomplished in less time with fewer options in a more fragile response. Caribou live at high latitudes where short summers constrain their response to changes in food supply. We measured the ability of female caribou to resist and tolerate changes in the quality and quantity of their food supply during winter and summer. Caribou resisted changes in food abundance and quality by changing food intake and physical activity with changes in daily temperature within each season. Peak food intake rose by 134% from winter pregnancy to summer lactation (98 vs. 229 g kg-0.75 d-1), as digestible requirements to maintain the body increased by 85% for energy (1,164 vs. 2,155 kJ kg-0.75 d-1) and by 266% for N (0.79 vs. 2.89 g N kg-0.75 d-1). Caribou required a diet with a digestible content of 12 kJ g-1 and 0.8% N in pregnancy, 18 kJ g-1 and 1.9% N in early lactation, and 11 kJ g-1 and 1.2% N in late lactation, which corresponds with the phenology of the wild diet. Female caribou tolerated restriction of ad lib. food intake to 58% of their energy requirement (680 vs. 1,164 kJ kg-0.75 d-1) during winter pregnancy and to 84% of their energy requirement (1,814 vs. 2,155 kJ kg-0.75 d-1) during summer lactation without a change in stress level, as indicated by fecal corticosterone concentration. Conversely, caribou can respond to increased availability of food with a spare capacity to process digestible energy and N at 123% (2,642 vs. 2,155 kJ kg-0.75 d-1) and 145% (4.20 vs. 2.89 g N kg-0.75 d-1) of those respective requirements during lactation. Robust responses to changes in food supply allow caribou to sustain reproduction, which would buffer demographic response. However, herds may decline when thresholds of behavioral resistance and physiological tolerance are frequently exceeded. Therefore, the challenge for managing declining populations of caribou and other robust species is to identify declines in robustness before their response becomes fragile.

АГРОКЛИМАТИЧЕСКИЕ РЕСУРСЫ ФОРМИРОВАНИЯ КАЧЕСТВА ЗЕРНА ЯРОВОЙ ПШЕНИЦЫ В РЕСПУБЛИКЕ БАШКОРТОСТАН

The results of the study of the dependence of the grain quality of soft spring wheat (Tríticum aestívum L.) on the main agroclimatic resources in the territory of the Republic of Bashkortostan are presented. Field experiments were carried out in different geographical locations of the republic according to the methodology of the State Variety Trial. Laboratory analyses of grain quality were carried out according to the methodology set forth in the State Standards. It has been established that the quality of soft spring wheat grain in the Republic of Bashkortostan largely depends on agroclimatic resources. In recent years, there has been a manifestation of global climate change on the territory of the republic. The amount of gluten in the grain depends to a large extent on the change in the average daily air temperature in June (r = 0.741) and to a slight extent on the average daily temperature in July (r = 0.359). The degree of dependence of gluten content increases significantly with an increase in the sum of air temperatures during the active vegetation of spring wheat (r = 0.812). The dependence of gluten content on the sum of temperatures in June and July is straightforward, and an increase in heat resources during the vegetation period of spring wheat plants by 10 °C contributes to an increase in the gluten content in grain by 0.73 %. Heat resources have a comparatively weak effect on other indicators of wheat grain quality. The correlation coefficient between gluten content and precipitation in July was 0.764. An increase in precipitation in July by 10 mm leads to a decrease in the gluten content in the grain of spring soft wheat by 0.49 %. High moisture availability also leads to the formation of soft spring wheat grain with low vitreousness (r = –0.547) and natural weight (r = –0.521). Moisture resources had a small effect on the gluten deformation index (r = 0.227). Precipitation in June has a weak effect on the quality indicators of spring soft wheat grain. The correlation coefficients between the sum of precipitation in June and the quality indicators were positive and ranged from 0.223 to 0.341

Association between air temperature and unintentional drowning risk in the United Kingdom 2012–2019: A nationwide case-crossover study

ObjectiveDrowning is a leading cause of death. The World Health Organization (WHO) and United Nations (UN) emphasise the need for population-level data-driven approaches to examine risk factors to improve water safety policies. Weather conditions, have the potential to influence drowning risk behaviours as people are more likely to spend time around water and/or undertake risky activities in aquatic spaces as a behavioural thermoregulatory response (e.g., seeking coolth). MethodsA case-crossover approach assessed associations between changes in daily maximum air temperature (data from the nearest weather station to each drowning event) and unintentional drowning risk using anonymous data from the validated UK Water Incident Database 2012–2019 (1945 unintentional deaths, 82% male). Control days were selected using a unidirectional time-stratified approach, whereby seven and 14 days before the hazard day were used as the controls. ResultsMean maximum air temperature on case and control days was 15.36 °C and 14.80 °C, respectively. A 1 °C increase in air temperature was associated with a 7.2% increase in unintentional drowning risk. This relationship existed for males only. Drowning risk was elevated on days where air temperature reached 15–19.9 °C (Odds Ratio; OR: 1.75), 20–24.9 °C (OR: 1.87), and ≥ 25 °C (OR: 4.67), compared with days <10 °C. The greatest elevations in risk appeared to be amongst males and when alcohol intoxication was suspected. Precipitation showed no significant association with unintentional drowning risk. ConclusionsIdentifying such relationships highlights the value of considering weather conditions when evaluating environmental risk factors for drowning, and may inform water safety policy and allocating resources to prevention and rescue.

МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ ВНУТРІШНЬОСТРУКТУРНИХ ТЕРМОНАПРУЖЕНЬ, ЩО ВИКЛИКАЮТЬСЯ ПОЛЯМИ ЗМІННОЇ ТЕМПЕРАТУРИ В КОМПОЗИТАХ ЗІ СТРИЖНЕВОЮ АРМАТУРОЮ

Introduction. Thermomechanical effects arising in heterogeneous composite materials under the influence of temperature significantly affect the strength and durability of structures made of them. These effects have a special influence on the thermal deformation of bridge and road structures under conditions of seasonal and daily changes in ambient temperature. They are caused by non-uniformity of the thermomechanical parameters of its fractions and fittings. Until now, the phenomenon of thermomechanical deformation of reinforced structures has not been sufficiently studied, therefore the tasks of their research are urgent. Problem Statement. The problem of the performed research is to establish the laws of thermomechanical deformation of composite materials (including cement concrete and asphalt concrete), which are reinforced with reinforcing rods, in the fields of variable temperatures. Purpose. The purpose of the work is to derive mathematical ratios that determine intrastructural thermal stresses in composites caused by variable temperature fields and heterogeneity of materials.

Assessing space and time changes in daily maximum temperature in the Ebro basin (Spain) using model‐based statistical tools

AbstractThere is continuing interest in the investigation of change in temperature over space and time. For this analysis, we offer statistical tools to illuminate changes temporally, at desired temporal resolution, and spatially, using data generated from suitable space–time models. The proposed tools can be used with the output from any suitable model fitted to any set of spatially referenced time series data. The tools to assess space and time changes include spatial surfaces of probabilities and spatial extents for events defined by exceeding a threshold. The spatial surfaces capture the spatial variation in the probability or risk of an exceedance event, while the spatial extents capture the expected proportion of incidence of an event for a region of interest. This approach is used analyse the changes in daily maximum temperature in an inland Mediterranean region (NE of Spain) in the period 1956–2015. The area is very heterogeneous in orography and climate, including the central Ebro valley and part of the Pyrenees. We use a collection of daily temperature series obtained from simulation under a Bayesian daily temperature model fitted to 18 stations in that area. The results for the summer period show that, although there is an increasing risk in all the events used to quantify the effects of climate change, it is not spatially homogeneous, with the largest increase arising in the centre of the Ebro valley and the Eastern Pyrenees area. The risk of an increase in the average daily maximum temperature from 1966–1975 to 2006–2015 higher than 1°C is higher than 0.5 over all of the region, and close to 1 in the previous areas. The extent of daily maximum temperature higher than the reference mean has increased 3.5% per decade. The mean of the extent indicates that 95% of the area under study has suffered a positive increment of the average temperature, and almost 70% an increment higher than 1°C.

Factors Affecting Indoor Temperature in the Case of District Heating

In this study, the influence of variables defining indoor temperature is studied, focusing on operational data and visual and technical inspections rather than the temperature control setpoints and occupancy schedule. This is incorrect because infiltration and insolation are highly variable. This results in lowering the temperature difference between the supply and return lines, overheating some spaces, lowering the indoor temperature in others, and poor hydronic balancing. The novelty lies in studying the actual operating condition of real district heating (DH) systems. The research hypothesis is that internal heat gains along with the infiltration of and variations in outdoor temperature cause daily changes in indoor temperature. These factors seem to be the primary reasons for the variations in supply and return temperature, if the rate of energy loss is not large in new office buildings constructed according to tightened contemporary energy conservation regulations. The saving effect is achieved by allowing the energy to be dumped into building envelopes; thus, the flow rate or supply temperature are varied in a narrower range. Dumping heat by using the storage capacity of building envelopes is suggested. The corrected design approach minimizes energy consumption and increases annual performance (e.g., by 14.1% here). Advantages are achieved by tuning a controller at a DH substation.

Operation Parameters Variation of Air Source Heat Pump According to the Outdoor Temperature

Air source heat pumps (ASHP), known as energy efficient systems, emerge as environmentally friendly and economical solutions for building heating. Unfortunately, the operating parameters of ASHPs and accordingly their performance are directly affected by the daily and seasonal temperature changes of the outside air. In this study, change in operation parameters of a selected ASHP with 3.4kW nominal heating capacity is investigated with a calculation method based on the logarithmic mean temperature difference, between -10°C to 18°C outdoor temperature range with 2°C steps, at constant compressor power. The study is verified with published COP data of the manufacturer. Results are shared with graphs that give the variation of refrigerant evaporation and condensation temperature and pressure, COP, and condenser heating load according to outdoor air temperature. A raise from -10°C to 18°C in outdoor temperature, increases the COP value from 3.38 to 5.49. Detection of the increase in evaporation pressure in parallel with the outdoor temperature may allow easy control of the refrigerant charge level with a manometer. This study can be a useful guide for researchers who aim to determine the outdoor temperature dependent operating parameters of an ASHP and for technical personnel who need this information in fields.

Effects of temperature oscillations on the accumulation of mercury and other trace metals in freshwater zooplankton (Daphnia magna)

Whereas many aquatic species experience daily temperature changes, it is unclear whether temperature fluctuations can affect the accumulation of trace metal independently from changes in mean temperature. Here, the impact of oscillating temperature (MTosc: 7/23 °C, 24 h/cycle) on the accumulation of both inorganic Hg (IHg) and monomethylmercury (MeHg) in Daphnia magna was investigated, by comparing it to a constant temperature treatment with the same average temperature (MTconst: 15 °C). The effects of mean temperature were tested by comparing this latter to a similar treatment with higher temperature (HTconst: 23 °C). Trophic pathway accumulation was estimated by using Chlorella vulgaris labeled with stable Hg isotopes, whereas the water pathway accumulation was estimated by directly spiking Hg isotope solutions into the D. magna incubators. The concentrations of IHg decreased in D. magna under oscillating temperature conditions for both trophic and water pathways by at least 42 % and 25 %, respectively, compared to the MTconst treatment. In contrast, the accumulation of MeHg was reduced only in the trophic pathway in these conditions, whereas it was enhanced in the water pathway. Patterns similar to IHg were observed for Fe, Zn, and Cu in the trophic pathway, but only for Cu in the water pathway. In contrast, no difference on the accumulation of rare earth elements was observed among temperature treatments. These results shed a new light on trace metal accumulation under near-realistic temperature conditions.