Mean Daily Air Temperature Research Articles

On the Sensitivity of the Daily Mean Air Temperature of Egypt to Boundary Layer Schemes Using a High-Resolution Regional Climate Model (RegCM4)

Introduction: Boundary layer processes play an important role in controlling the daily mean air temperature through exchange of turbulent fluxes of water and energy between the ground surface and the atmosphere. Therefore, it is important to explore the role of boundary layer parameterization in simulating the daily mean air temperature particularly on a regional scale. Methods: To accomplish this task, two simulations were conducted to assess the sensitivity of the mean air Temperature (TMP) of Egypt to boundary layer schemes (Holtslag; HOLT and University of Washington; UW) within the framework of the Regional Climate Model (RegCM4). The RegCM4 was downscaled by the ERA-Interim reanalysis of 1.5 degrees with 25 km horizontal grid spacing over the period 1997-2017. Additionally, ERA5 reanalysis product was used as the observational dataset for the variables: the Total Cloud Cover (CLT), surface short and long wave radiation fluxes (RSDS and RLDS), Skin Temperature (TS), surface Wind Speed (WS), Sensible Heat Flux (HFSS) and TMP. Results: There is no difference between HOLT and UW regarding the CLT and RSDS; while the UW reduces the bias of the RLDS and WS relative to HOLT particularly in the summer and autumn seasons in comparison with ERA5. Furthermore, HOLT and UW schemes showed a considerable impact on the simulated TS. For instance, UW reduces the TS bias relative to HOLT in all seasons but in the spring and winter seasons; UW induces a negative bias more than HOLT. Concerning the HFSS, UW shows a higher bias than HOLT mainly in the summer and autumn seasons. Because of the noted changes of the simulated HFSS and TS, the UW succeeds in reducing the warm bias of the TMP (noted in the HOLT) in all seasons in comparison with the ERA5. With respect to in-situ observations, the HOLT/UW performance varies with the location as well as the month. Conclusion: The UW scheme can be recommended for future studies concerning the future climate change of Egypt concerning the regional scale. However for a point scale, caution is needed in interpreting the results with respect to the in-situ observations except for Asswan where HOLT can be recommended.

Influence of Direct-Downscaling and One-Way Nesting on Daily Mean Air Temperature of Egypt Using the RegCM4

Daily mean air temperature (TMP) is an important indicator for a climate change study and it reflects the daily changes of the maximum and minimum air temperature. Downscaling of a General Circulation Model (GCM) to a regional scale is important to ensure accurate simulation of the TMP. To address this issue, a comparison was conducted between Direct Downscaling (DIR) and one-way nesting (NEST) using a Regional Climate Model (RegCM4) in the period 1997-2017 over Egypt. The ERA-Interim reanalysis of 1.5 degrees (EIN15) was used as the atmospheric forcing to downscale the RegCM4 over Egypt, while the fifth generation ECMWF atmospheric reanalysis was used to evaluate the RegCM4 concerning the Total Cloud Cover (CLT), surface short and longwave radiation fluxes (RSDS and RLDS), ground temperature (TS), sensible heat flux (HFSS) and TMP. Results showed that there was no difference between DIR and NEST regarding the CLT and RSDS; while the NEST overestimated the RLDS more than the DIR particularly in the summer and autumn seasons in comparison with ERA5. Furthermore, the difference between DIR and NEST as the NEST overestimated the TS more than DIR in all seasons and in particular the summer and autumn seasons. This noted overestimation propagated to the HFSS explaining the high warm bias in the simulated TMP; which was higher in NEST than DIR. Such findings suggest that DIR was only affected by uncertainty associated with the EIN15. Additionally, this uncertainty was amplified using NEST because the uncertainty of EIN15 first propagated to the mother domain and then from the mother to the nested one. Despite of observed biases, DIR shows promising results more than NEST. Therefore, DIR can be recommended for future climate studies over Egypt.

Charakterystyka okresu wegetacyjnego w Lasach Doświadczalnych SGGW w Rogowie w latach 1951–2020

The growing season length indices derived from air temperature are frequently used in climate monitoring applications as well as to predict the response of forest ecosystems to climate change. The indicator most widely used in the studies of forest ecosystems is the length of the thermal growing season (temp ≥5°C), less commonly the parameters of the forest growing season (temp ≥10°C). However, only a few studies used long-term series of temperature measurements in the forest. In this article, we determined the temporal changes in the parameters of the thermal (TGS) and forest (FGS) growing season in the Experimental Forests of the Warsaw University of Life Sciences in Rogów (51o40’N, 19o55’E, h = 194 m MSL) in the years 1951–2020. The analysis is based on the dataset (daily mean air temperature) obtained from a meteorological station located near the forest complex and from a forest under-canopy station located in a more than 120-year-old fresh mixed forest. The results show a significant extension of the growing season in 1951–2020, the TGS lasted on average 2.8 days/10 years, and the FGS 2.4 days/10 years. The extension of the TGS and FGS was a consequence of both its earlier start and later end. The start of the TGS was characterized by a statistically significant negative trend (1.3 days/10 years), and most changes were characteristic for the last three decades (4.4 days/10 years). The last 30 years were also characterized by a statistically significant trend towards the later end of the TGS. The TGS in 1991–2020 was longer than in 1951–1980 and 1971–2000 by 9 days, while in 1981–2010 by 5 days. Changes in the length of the TGS resulted primarily from its earlier beginning: in the multi-year period 1991–2020, the TGS started 7 days earlier than in 1951–1980. In the case of the FGS, these changes were weaker, although there was a statistically significant negative trend in the start dates and a positive trend in the FGS length. The FGS started almost a month later than the TGS (average on April 28) and ended 4 weeks earlier (average on October 5) and lasted 160 days. TGS in the forest was shorter than outside the forest by 3 days, and FGS by 1 day. The acceleration of the beginning of TGS during the last three decades was faster than the beginning of the frost-free period, indicating a possible increase in vegetation exposure to spring frost. This may pose a threat to the development of plants in the first phase of vegetation.

A matter of size and shape: Microclimatic changes induced by experimental gap openings in a sessile oak–hornbeam forest

Forest management integrating nature conservation aspects into timber production focuses increasingly on small-scale interventions. However, the ecological consequences of gap cuttings remain ambiguous in oak-dominated forests. In the Pilis Gap Experiment, we analyze how combinations of different gap shapes (circular and elongated), and gap sizes (150 m2 and 300 m2) affect the microclimate and biota of a mature sessile oak-hornbeam forest in Hungary. We first report the changes in direct and diffuse light, soil moisture, daily air and soil temperatures, and relative air humidity in the experimental cuttings in the vegetation season directly following their implementation. Diffuse light had a central maximum and a concentric pattern. Direct light was distributed along a north-south gradient, with maxima in northern gap parts. Soil moisture was determined by gap shape: it increased significantly in the center of circular gaps, with multiple local maxima in the southern-central parts of large circular gaps. Its pattern was negatively related to direct light, and larger spatial variability was present in circular than in elongated gaps. The daily mean air temperatures at 1.3 m increased in all, especially in large gaps. Soil and ground-level temperatures remained largely unchanged, reflecting on light and soil moisture conditions affecting evaporative cooling. Relative humidity remained unaltered. Even though the opening of experimental gaps changed microclimatic conditions immediately, effect sizes remained moderate. Gap size and gap shape were both important determinants of microclimate responses: gap size markedly affected irradiation increase, gap shape determined soil moisture surplus, while soil and air temperatures, and air humidity depended on both components of the gap design. We conclude that 150–300 m2 sized management-created gaps can essentially maintain forest microclimate while theoretically providing enough light for oak regeneration; and that the manipulation of gap shape and gap size within this range are effective tools of adaptive management.

Multiple factors co-limit short-term in situ soil carbon dioxide emissions.

Soil respiration is a major source of atmospheric CO2. If it increases with warming, it will counteract efforts to minimize climate change. To improve understanding of environmental controls over soil CO2 emission, we applied generalized linear modeling to a large dataset of in situ measurements of short-term soil respiration rate, with associated environmental attributes, which was gathered over multiple years from four locations that varied in climate, soil type, and vegetation. Soil respiration includes many CO2-producing processes: we theorized that different environmental factors could limit each process distinctly, thereby diminishing overall CO2 emissions. A baseline model that included soil temperature, soil volumetric water content, and their interaction was effective in estimating soil respiration at all four locations (p < 0.0001). Model fits, based on model log likelihoods, improved continuously as additional covariates were added, including mean daily air temperature, enhanced vegetation index (EVI), and quadratic terms for soil temperature and water content, and their interactions. The addition of land cover and its direct interactions with environmental variables further improved model fits. Significant interactions between covariates were observed at each location and at every stage of analysis, but the interaction terms varied among sites and models, and did not consistently maintain importance in more complex models. A main-effects model was therefore tested, which included soil temperature and water content, their quadratic effects, EVI, and air temperature, but no interactions. In that case all six covariates were significant (p < 0.0001) when applied across sites. We infer that local-scale soil-CO2 emissions are commonly co-limited by EVI and air temperature, in addition to soil temperature and water content. Importantly, the quadratic soil temperature and moisture terms were significantly negative: estimated soil-CO2 emissions declined when soil temperature exceeded 22.5°C, and as soil moisture differed from the optimum of 0.27 m3 m-3.

Effects of Temperatures and Heatwaves on Occupational Injuries in the Agricultural Sector in Italy.

The effects of heat on health have been well documented, while less is known about the effects among agricultural workers. Our aim is to estimate the effects and impacts of heat on occupational injuries in the agricultural sector in Italy. Occupational injuries in the agricultural sector from the Italian national workers' compensation authority (INAIL) and daily mean air temperatures from Copernicus ERA5-land for a five-year period (2014-2018) were considered. Distributed lag non-linear models (DLNM) were used to estimate the relative risk and attributable injuries for increases in daily mean air temperatures between the 75th and 99th percentile and during heatwaves. Analyses were stratified by age, professional qualification, and severity of injury. A total of 150,422 agricultural injuries were considered and the overall relative risk of injury for exposure to high temperatures was 1.13 (95% CI: 1.08; 1.18). A higher risk was observed among younger workers (15-34 years) (1.23 95% CI: 1.14; 1.34) and occasional workers (1.25 95% CI: 1.03; 1.52). A total of 2050 heat-attributable injuries were estimated in the study period. Workers engaged in outdoor and labour-intensive activities in the agricultural sector are at greater risk of injury and these results can help target prevention actions for climate change adaptation.

Impacts of wintertime meteorological variables on decomposition of Phragmites australis and Solidago canadensis in the Balaton System

A field experiment was carried out in plant litter decomposition at three sites of the Balaton System (Balaton — Kis Balaton wetland — Zala Mouth) differing in their environment type during winter 2019/2020. The largest freshwater shallow lake in Central Europe (Carpathian Basin) is the Balaton, with a surface area of about 600 km2 and an average depth of 3.25 m. Right around the lake, a nutrient filtering system, the Kis-Balaton wetland, is functioning to avoid water deterioration and eutrophication. The aim of the study was to investigate crop-weather relations in two sample species, the widely distributed native P. australis and the allied S. canadensis incubated beneath the water using leaf-bag technique to characterise plant organ decomposition. Based on our results, the most consistent meteorological variable regarding decomposition process was global radiation (r = − 0.62* to − 0.91**; r: correlation coefficient; * and ** mean that correlations are significant at the 0.05 and 0.01 levels), in each treatment. In modelling the decomposition process, out of eight meteorological variables, only the daily mean air temperatures and humidity were excluded from regression equations. On dominatingly windy days, with the increase in water temperature of the Zala Mouth, the sensitivity of the decomposition of S. canadensis litter tended to decrease as compared to P. australis. The remaining litter masses were in a Kis-Balaton > Balaton > Zala order, contrasting the water temperature gradient that decreased from the Zala to the Kis-Balaton wetland under wind-dominated conditions. Considering all sampling places in three aquatic ecosystems, there was a 2.2 and a 2.7% daily mean detritus mass loss in P. australis and S. canadensis, respectively. We concluded that the invasive S. canadensis litter decomposed more quickly than those of native P. australis, irrespective to sampling site. Increase in winter water temperature significantly promoted the litter decomposition of both plant species. The originality of the study is that it quantifies the litter decomposition for an Eastern European wetland, during wintertime.

Flight activity and dispersal of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) across a mixed agricultural landscape in southern Australia

To better understand the field ecology of stored grain beetles in southern Australia we monitored the flight activity of Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst) over a 2 year period. We used target-specific pheromone lures and Lindgren funnel traps in open fields, at grain storages, and in remnant native vegetation. Over 35,000 R. dominica and 2,500 T. castaneum were caught. Significantly more R. dominica (46.4%) were caught in areas of remnant vegetation than at storage sites (29.2%) or in open fields (24.4%), suggesting this species may be utilising non-grain food sources in some areas. In contrast, the majority of T. castaneum (45.4%) were caught adjacent to storages. An intense summer heatwave (14 day mean maximum air temperature 41.9 °C) corresponded to captures of both species declining to near zero until the following spring. Sex ratios of both species varied significantly over time but were unaffected by habitat type. Two mark/release/recapture (MRR) trials using laboratory-reared R. dominica were conducted using a 1 km trap array and pheromone lures. The recovery rate for marked beetles in the first trial was 1.41%, however a subsequent experiment comparing fresh and weathered lures showed that lure attractancy declines to 50% between 3 and 4 days after deployment during hot weather (mean daily maximum air temperature 29.4 °C). When the MRR trial was repeated with lures replaced at shorter (2 day) intervals, the recovery rate rose to 3.27% and the number of wild R. dominica captured increased proportionately. The short half-life of rubber septum-based R. dominica pheromone lures needs to be considered when designing surveillance programs, particularly if attempts are being made to correlate R. dominica dispersal patterns to short-term weather events.

Cambial phenology and wood formation of Korean pine in response to climate change in Changbai Mountain, Northeast China

Korean pine (Pinus koraiensis Sieb. et Zucc.) is a highly ecological and economic species due to its rarity, varied usage and favorable effect on the environment. To better understand the adaptation strategies of intra-annual radial growth of Korean pine to local environmental regimes, we continuously monitored the cambial activity and wood formation in northeastern China weekly from April to October across the two consecutive years of 2020 and 2021 using Trephor. The results indicated that the warmer spring in 2021 resulted in an earlier onset of cambial activity compared to that of 2020 (DOY 118 vs DOY129), but the cessation of wood formation was similar (DOY 250 vs DOY 248). In both years, similar thresholds were estimated using logistic regression, xylem growth was active when the daily mean air temperature was 11.5 °C. Sensitivity analysis revealed that 86% of xylem growth was attributed to the growth rate and 14% to its duration. The total number of xylem cells was positively correlated with air temperature, soil temperature and relative humidity, and negatively correlated with vapor pressure deficit and soil water content in both years. Temperature is the main factor limiting the growth of Korean pine. Our findings complement a description of cambial phenology and wood formation dynamics of Korean pine at cellular levels and provide a better understanding of the climate-growth relationship, which will enable the improvement of climate-growth models used to predict climate change.

Seasonal variations in presenting symptoms and signs of dry eye disease in Norway

The study investigated the seasonal variations of presenting symptoms and signs of dry eye disease (DED) in Norway. 652 consecutive DED patients examined between August 2012 and May 2015 in Oslo, Norway, were included. Presenting symptoms and signs were related to the season according to when each patient was examined. Weather report data from the examination day were compared with the presenting symptoms and signs. Oslo's mean seasonal temperatures during spring, summer, fall, and winter were 6.4 °C, 15.6 °C, 9.3 °C, and − 2.1 °C, respectively. Dry eye severity level and self-reported symptoms measured by the Ocular surface disease index questionnaire did not differ between seasons. Schirmer I was lower during summer than in other seasons (P < 0.01). The percentage of patients with a pathological tear meniscus height (< 0.2 mm) was higher during fall (P < 0.01) and lower during winter (P < 0.05) compared to the other seasons. Signs and symptoms of DED generally did not correlate with weather report data, although intraocular pressure was weakly associated with mean daily air temperature (r = − 0.22; P < 0.001). Neither dry eye severity level nor dry eye symptoms differ between seasons in Oslo, Norway. However, some parameters for assessing DED show seasonal variations (Schirmer I and tear meniscus height), which are essential to consider when examining patients with DED.

Assessing Impact of Temperature Variability of Climate Change on Mortality Based on Multiple GCM Projections in China

Gradually increasing durations of high temperature caused by climate change harm the health of individuals and then lead to death. This study aimed to investigate the relationship between durations of different daily mean air-temperature categories and mortality in China and forecast future mortality changes in China for 2020–2050 under Representative Concentration Pathways (RCP)4.5 and RCP8.5 scenarios. The daily mean air temperature was divided into 10 categories, and the days under each air-temperature category were counted during the period of 2000–2015. Then, the connection between the days of each of the 10 air-temperature categories and mortality was established using the semi parametric regression model. Results indicate that the days of the &gt;32 °C category have the largest impact on mortality in China, with the death rate increasing by 23‰ for one additional day. Predictions reveal that mortality in China will increase 25.48% and 26.26% under the RCP4.5 and RCP8.5 scenarios, respectively. Moreover, the mortality of 86 regions in western China will increase 30.42%. Therefore, in the future, the increasing duration of days of high temperatures will raise the mortality rate in China and aggravate the mortality gap between developed and underdeveloped regions.

Assessing the Interplay between Weather and Septoria Leaf Blotch Severity on Lower Leaves on the Disease Risk on Upper Leaves in Winter Wheat.

Septoria leaf blotch (SLB) is among the most damaging foliar diseases of wheat worldwide. In this study, data for seven cropping seasons (2003-2009) at four representative wheat-growing sites in the Grand-Duchy of Luxembourg (GDL) were used to assess SLB risk on the three upper leaves (L3 to L1, L1 being the flag leaf) based on the combination of conducive weather conditions, simulated potential daily infection events by Zymoseptoria tritici, and SLB severity on lower leaves between stem elongation and mid-flowering. Results indicated that the variability in SLB severity on L3 to L1 at soft dough was significantly (p &lt; 0.05) influenced by the disease severity on the lower leaf L5 at L3 emergence and the sum of daily mean air temperature between stem elongation and mid-flowering. Moreover, analyzing the predictive power of these variables through multiple linear regression indicated that the disease severity on L5 at L3 emergence and mild weather conditions between stem elongation and mid-flowering critically influenced the progress of SLB later in the season. Such results can help fine tune weather-based SLB risk models to guide optimal timing of fungicide application in winter wheat fields and ensure economic and ecological benefits.

Activities of H2O2-Converting Enzymes in Apple Leaf Buds during Dormancy Release in Consideration of the Ratio Change between Bud Scales and Physiologically Active Tissues

Hydrogen peroxide-converting enzyme activities in leaf buds of the apple cultivar Idared during the transition from dormancy release to the ontogenetic development were investigated. For this purpose, leaf buds were collected from 26 March 2021 (DOY = day of the year 85) to 23 April 2021 (DOY 113) and the air temperature was continuously monitored. Enzyme assay protocols for catalase (CAT), intracellular peroxidase (POX), and cell wall-bound peroxidase (cwPOX) in apple leaf buds were successfully established based on published protocols. All enzymes showed considerable changes in activity during the observation period. Fluctuation in daily mean air temperatures seemed not to affect the activities of POX and CAT, whereas severe drops in daily mean air temperature may have interrupted the assumed trajectory of cwPOX activity during the stage of ontogenetic development. In addition, the importance of considering changes in the ratio between physiologically active tissues and bud scales when investigating physiological changes in buds during the phase of dormancy release and ontogenetic development is discussed. A new reference system, namely the “adjusted dry weight” [aDW], is proposed to circumvent this shift in ratios when working with scaled buds.

Summer dormancy of Myricaria laxiflora to escape flooding stress: Changes in phytohormones and enzymes induced by environmental factors

Dormancy is an adaptation mechanism of plants to environmental stress. Myricaria laxiflora undergoes a long period of flooding stress every year. In order to determine whether this species escapes flooding stress through dormancy, young branches and leaves were collected at different time points before the onset of flooding, and changes in the content/activity of hormones/enzymes that are closely involved in plant growth were monitored. The inducing environmental factors of summer dormancy were identified. The branches and leaves of M. laxiflora showed the following trends as summer flooding approached: (1) gradual increase in the abscisic acid content; (2) gradual decrease in the gibberellin and cytokinin contents; and (3) a continuous decrease in the activities of malate dehydrogenase (MDH), ribulose diphosphate carboxylase (RuBisCo), and glycolate oxidase (GLO). Pearson correlation analysis revealed (1) daylight duration was highly correlated with the hormone content and enzyme activity; (2) the daily mean air temperature (DMAT) was significantly correlated with the cytokinin content. These findings suggest that daylight duration was the main environmental factor leading to changes in the phytohormone content and enzyme activity as well as leading to summer dormancy. M. laxiflora undergoes dormancy before the onset of summer flooding to escape summer flooding stress. Our data indicate that summer flooding does not impede the survival and growth of M. laxiflora.

Effects of heat exposure on occupational injuries in the agricultural sector in Italy

Background and aim – The health effects of extreme temperatures at population level are well known. However, the effects on occupational injuries in different sectors have been scarcely investigated. Methods - We collected work-related injuries in the agriculture sector occurring in the 8,090 Italian municipalities from the Italian national workers’ compensation authority (INAIL) between 2014-2018. Daily air temperatures from Copernicus ERA5-land were used to define exposure at municipality level. First, we applied distributed lag non-linear models (DLNM) to estimate the association between daily mean air temperature and injuries at regional level; then meta-analysed results to have overall estimates. The relative risk (RR) and attributable cases of agriculture-related injuries for an increase in mean temperature above the 75th percentile were estimated, as well as heatwave effects. Analysis were also stratified by age, duration of leave and professional qualification. Results - Analysis were conducted on 150,422 agricultural injuries. The overall relative risk of agricultural work-related injuries for an increase in temperatures was 1.13 (95%CI: 1.08; 1.18). The number of injuries attributable to heat is of 2050 cases in the considered period. A higher risk was observed among young workers (1.23 95% CI: 1.14; 1.34) and seasonal workers (1.25 95% CI: 1.03; 1.52). When considering duration of leave, a proxy of severity of heat-related injuries, the greatest risk and frequency was observed for short duration between 0-14 days (1.21 95% CI: 1.10; 1.33) with a decreasing trend. Considering extreme heat wave events, the risk of injuries in the agricultural sector was of 1.04 (95% CI: 1.01; 1.08). Conclusions - Occupational exposure to extreme temperatures is a critical issue considering climate change especially among sectors engaged in outdoor and labour-intensive activities such as the agricultural sector. These results can help promote specific prevention actions for workers. Keywords - Work-related injuries; heat waves; agricultural sector.

Long-term effects of air temperature on cardiopulmonary outcomes in prospective European cohort studies

BACKGROUND AND AIM: Short-term health effects of air temperature have been well recognized. However, little is known about the effects of prolonged exposure to non-optimal air temperatures, particularly at the individual level. This study assessed long-term temperature effects on cardiopulmonary (CPD) outcomes using data collected in four prospective European cohorts. METHODS: Participants of the KORA (Augsburg, Germany), RoLS (Rome, Italy), CONOR (Norway), and UK Biobank (UK) cohorts were included in the current analysis. Their vital status and incident diseases were identified through death and disease registries as well as follow-up surveys. Annual mean and standard deviation (SD) of air temperature were calculated for each participant and follow-up year based on the daily mean air temperature at residences estimated by spatial-temporal models. We applied cohort-specific Cox proportional hazard models with adjustment for individual characteristics and time trends, using the distributed lag non-linear model approach, to assess the associations of long-term air temperature with CPD mortality and morbidity. Random-effects meta-analysis was used to pool the cohort-specific estimates. RESULTS: In the RoLS cohort, we observed a monotonically increasing risk for cardiovascular mortality associated with increasing annual mean and SD of temperature. For an increment from the 75th to the 95th percentile in the annual mean and SD, the hazard ratios for cardiovascular mortality were 1.055 (95% CI: 1.029, 1.081) and 1.151 (95% CI: 1.060, 1.251), respectively. Besides, increasing annual SD showed an indication of being associated with increased respiratory mortality risk. In the KORA cohort, no effects were observed for annual mean temperature or SD on CPD mortality and morbidity. Cohort-specific analyses in Norway and UK and the meta-analysis are ongoing. CONCLUSIONS: This study provides evidence for long-term air temperature effects on CPD outcomes but also indicates heterogeneity in such effects among four European cohorts. KEYWORDS: Air temperature, long-term, cardiopulmonary mortality, cohorts

Short-term effects of heat on respiratory mortality and morbidity in Germany – small-area analysis in the framework of the EXHAUSTION project

Background and Aim: Short-term associations between heat and respiratory mortality and morbidity have been well recognized. However, most studies were conducted in major cities, whereas evidence for more rural areas is limited. In this study, we assessed the short-term associations between air temperature and cause-specific respiratory mortality and hospital admissions in the warm season (May-September) in Germany at a small-area level. Methods: Daily counts of mortality and hospital admissions for respiratory diseases, chronic obstructive pulmonary disease, asthma, lower respiratory tract infections, and pneumonia from 2000 to 2016 were obtained for Germany at the small-area level. Small areas were defined as districts for mortality data and municipalities for hospital admission data. Daily mean air temperatures estimated by a spatio-temporal model were assigned to each small area. We first applied small area-specific Poisson regression allowing for overdispersion, using Distributed Lag Non-linear Models to assess the heat effects at lag 0-1 days (average of same- and previous-day temperatures). Random-effects meta-analysis was then used to pool the small area-specific estimates. Besides, we conducted subgroup analyses to investigate effect modification by age and sex. Results: We observed increased risks for all investigated cause-specific respiratory mortality and hospital admissions associated with heat. The strongest heat effect was found for pneumonia. For an increment from the 75th to the 99th percentile of the temperature distribution, the pooled risk ratio was 1.49 (95% CI: 1.42, 1.57) for pneumonia mortality and 1.20 (95% CI: 1.19, 1.22) for pneumonia hospital admissions. The heat effects were stronger among the elderly (75+ years) and females. Conclusions: Using data from both urban and rural areas, our study suggests the adverse heat effects on respiratory mortality and morbidity in the warm season in Germany. These heat effects were more pronounced among the elderly and females. Keywords: Air temperature, heat, respiratory, mortality, hospital admissions

The association of COVID-19 incidence with temperature, humidity, and UV radiation – A Global multi-city analysis

Background and Aim. The possible associations of COVID 19 transmission and meteorological factors is a topic of scientific debate. A multitude of studies have been conducted worldwide, with inconsistent findings. However, often these had methodological issues, e.g. did not exclude important confounding factors, or had limited geographic or temporal resolution. Methods. We analysed data from 455 cities across 20 countries around the globe over an observation period before the vaccine roll out began, ranging from 3 February to 31 October 2020. We used a time-series analysis that assumes a quasi-Poisson distribution of the cases and incorporates distributed lag non-linear modelling for the exposure association at city-levels while considering effects of autocorrelation, long-term trends and day of the week. The confounding by governmental measures was accounted by incorporating the Oxford Governmental Stringency Index. The effects of daily mean air temperature, relative and absolute humidity, and UV radiation were estimated by applying a meta-regression of local estimates with multi-level random effects for location, country, and climatic zone. Results. We found that air temperature and absolute humidity influenced the spread of COVID-19 over a lag period of 15 days. Pooling the evidence globally showed that overall low temperatures (7.5&amp;#xb0;C compared to 17.0&amp;#xb0;C) and low absolute humidity (6.0 g/m³ compared to 11.0 g/m³) were associated with higher COVID 19 incidences (RRtemp=1.33 with 95%CI: 1.08; 1.64 and RRAH=1.33 with 95%CI: 1.12; 1.57). For RH and UV no evidence of an association was found. These results were robust to sensitivity analysis. However, the study results also emphasised the heterogeneity of these associations in different countries. Conclusion. Globally, our results suggest that comparatively low temperatures and low absolute humidity were associated with increased risks of COVID 19 incidence. However, this study underlines regional heterogeneity of weather-related effects on COVID-19 transmission. Key words: Temperature, Humidity, UV Radiation, COVID-19

The association of COVID-19 incidence with temperature, humidity, and UV radiation – A global multi-city analysis

Background and aimThe associations between COVID-19 transmission and meteorological factors are scientifically debated. Several studies have been conducted worldwide, with inconsistent findings. However, often these studies had methodological issues, e.g., did not exclude important confounding factors, or had limited geographic or temporal resolution. Our aim was to quantify associations between temporal variations in COVID-19 incidence and meteorological variables globally. MethodsWe analysed data from 455 cities across 20 countries from 3 February to 31 October 2020. We used a time-series analysis that assumes a quasi-Poisson distribution of the cases and incorporates distributed lag non-linear modelling for the exposure associations at the city-level while considering effects of autocorrelation, long-term trends, and day of the week. The confounding by governmental measures was accounted for by incorporating the Oxford Governmental Stringency Index. The effects of daily mean air temperature, relative and absolute humidity, and UV radiation were estimated by applying a meta-regression of local estimates with multi-level random effects for location, country, and climatic zone. ResultsWe found that air temperature and absolute humidity influenced the spread of COVID-19 over a lag period of 15 days. Pooling the estimates globally showed that overall low temperatures (7.5 °C compared to 17.0 °C) and low absolute humidity (6.0 g/m3 compared to 11.0 g/m3) were associated with higher COVID-19 incidence (RR temp =1.33 with 95%CI: 1.08; 1.64 and RR AH =1.33 with 95%CI: 1.12; 1.57). RH revealed no significant trend and for UV some evidence of a positive association was found. These results were robust to sensitivity analysis. However, the study results also emphasise the heterogeneity of these associations in different countries. ConclusionGlobally, our results suggest that comparatively low temperatures and low absolute humidity were associated with increased risks of COVID-19 incidence. However, this study underlines regional heterogeneity of weather-related effects on COVID-19 transmission.

The day-to-day temperature variability method as a tool for urban heat island analysis: A case of Zagreb-Grič Observatory (1887–2018)

The paper applies the relatively new day-to-day (DTD) method to analyse the day-to-day variability of minimum, mean and maximum daily air temperatures measured at the Zagreb Grič Observatory in the period from 1878 to 2018. The observatory is located in the centre of this rapidly developed city. The DTD values were calculated and compared for the whole year and for the warm period of the year (June 15th to September 15th). Neither positive nor negative trends in the time series of mean daily, DTDmean, and minimum daily, DTDTmin, day-to-day temperatures variabilities were found. There was a statistically significant difference in the behaviour of the series in the sub-period 1887–1958 and in the sub-period 1959–2018, when the maximum daily temperatures series, DTDTmax, and the difference between the maximum and minimum daily temperatures, ΔDTD, were considered. The DTD variabilities appeared in the annual series and those for the warm period of the year. Statistically lower inter-day variabilities were observed over the last 60 years. Variabilities in the warm period of the year, DTDTmin, are significantly lower than for the year as a whole. The variabilities in annual differences, ΔDTD, are significantly lower than those in the warm period of the year.