Diurnal Temperature Variations Research Articles

Effects of alternating positive and negative temperature curing on the mechanical properties of ultra-high performance concrete

The Tibetan region is characterized by long winters and large diurnal temperature variations. Using prefabricated bridges combined with a small amount of cast-in-place concrete joints can address the challenging construction environment. To extend the bridge construction window for concrete in the joint, the performance of Ultra-High Performance Concrete (UHPC) under alternating positive and negative temperature environments was investigated. The effects of curing conditions (−10 to 10 °C and natural curing), different proportions of sulfoaluminate cement (0% / 6%), different concrete materials (UHPC/NC), and the presence of antifreeze admixtures on the macro-strength and late-stage microstructure of UHPC were explored. The results indicated that the slump expansion of the prepared UHPC in this study exceeds 600 mm. Alternating temperature environments significantly degrade the mechanical properties of UHPC without antifreeze admixtures. However, for self-made UHPC with antifreeze admixtures, the formed early structure can prevent freeze-thaw damage as long as the critical antifreeze strength is reached. After the temperature rebounded, the later-stage strength of UHPC can continue to develop and reach the compressive strength of samples that had not been exposed to low-temperature curing. The appropriate addition of sulfate aluminate cement positively affected the early compressive strength (1 day) and elastic modulus of UHPC. It also reduces the drying shrinkage of UHPC.

On the Contribution of Transient Diabatic Processes to Ocean Heat Transport and Temperature Variability

Abstract Time-varying processes contribute to ocean heat transport and are important to understand for accurate climate modeling. While past studies have quantified time-varying contributions to advective transport, less attention has been given to diabatic processes such as surface forcing and mixing. Using a global eddy-permitting ocean model we quantify the contribution of time-variable processes to meridional and diathermal (warm to cold) heat transport at different time scales using a temporal eddy-mean decomposition performed in the temperature–latitude plane. Time-varying contributions to meridional heat transport occur predominantly at mesoscale eddy-dominated midlatitudes and in the tropics, associated with the seasonal cycle and tropical instability waves. The seasonal cycle is a dominant driver of surface flux– and mixing-driven diathermal heat transports. Nonseasonal (and nondiurnal) processes contribute up to about 10% of the total. We show that transient contributions to diathermal heat transport can be interpreted as sources of Eulerian temperature variance. We thus extend recent work on the drivers of temperature variability by evaluating the role of mixing. Mixing dampens seasonal and diurnal temperature variability, except near the equator where it can be a source of seasonal variability. At mesoscale time scales mixing drives variability within and near the base of the boundary layer, the mechanisms of which are explored using a column model. We suggest that climate models that do not resolve the mesoscale may be missing the rectified heat transport associated with high-frequency diabatic processes, in addition to the adiabatic eddy fluxes that are commonly parameterized. Significance Statement Ocean heat transport plays a key role in determining how the climate responds to changes in forcing. This transport is influenced by a range of processes that vary with time. Previous research has quantified time-varying sources of lateral heat transport, such as mesoscale eddies and overturning circulation cells. However, time-varying “diabatic processes,” such as surface forcing and unresolved turbulent mixing, have received less attention. Here, we quantify these effects using a global ocean model. We find a dominant role for the seasonal cycle in driving diabatic heat transport, but processes on shorter time scales also contribute. Our results suggest that temporal variations in turbulent mixing are an important contributor to heat transport but may not be resolved in coarse-resolution climate models.

All-cause mortality attributable to long-term changes in mean temperature and diurnal temperature variation in China: a nationwide quasi-experimental study

Previous studies have demonstrated an association between short-term exposure to ambient temperature and mortality. However, the long-term effects of elevated temperature and temperature variability on mortality have remained somewhat elusive in epidemiological studies. We conducted a comprehensive epidemiological study utilizing Chinese population census data from 2000 and 2010. Census-derived demographic and socioeconomic factors were paired with temperature data from the European Re-Analysis Land Dataset across 2823 counties. We employed a difference-in-difference approach to quantitatively examine the relationship between all-cause mortality and annual exposure to mean temperature and diurnal temperature range (DTR). Additionally, we evaluated the potential effects of socioeconomic and environmental covariate modifications on this relationship and calculated the attributable mortality. Lastly, we projected excess deaths attributable to annual temperature exposure under various shared socioeconomic pathways (SSPs, e.g. SSP126, SSP370, and SSP585). For each 1 °C rise in annual mean temperature and DTR, the mortality risk could increase by 6.12% (95% CI: 0.84%, 11.69%) and 7.72% (95% CI: 3.75%, 11.84%), respectively. Counties with high labor-force ratios and high NO2 and O3 concentrations appeared to be sensitive to the annual mean temperature and DTR. Climate warming from 2000 to 2010 may have resulted in 5.85 and 14.46 additional deaths per 10 000 people attributable to changes in annual mean temperature and DTR, respectively. The excess mortality related to changes in annual mean temperature and DTR is expected to increase in the future, with special attention warranted for long-term temperature changes in Southwest China. Our findings indicate that long-term mean temperature and DTR could significantly impact mortality rates. Given the spatial heterogeneity of increased mortality risk, the formulation of region-specific strategies to tackle climate change is crucial.

Diurnal switches in diazotrophic lifestyle increase nitrogen contribution to cereals

Uncoupling of biological nitrogen fixation from ammonia assimilation is a prerequisite step for engineering ammonia excretion and improvement of plant-associative nitrogen fixation. In this study, we have identified an amino acid substitution in glutamine synthetase, which provides temperature sensitive biosynthesis of glutamine, the intracellular metabolic signal of the nitrogen status. As a consequence, negative feedback regulation of genes and enzymes subject to nitrogen regulation, including nitrogenase is thermally controlled, enabling ammonia excretion in engineered Escherichia coli and the plant-associated diazotroph Klebsiella oxytoca at 23 °C, but not at 30 °C. We demonstrate that this temperature profile can be exploited to provide diurnal oscillation of ammonia excretion when variant bacteria are used to inoculate cereal crops. We provide evidence that diurnal temperature variation improves nitrogen donation to the plant because the inoculant bacteria have the ability to recover and proliferate at higher temperatures during the daytime.

Combined modelling of annual and diurnal land surface temperature cycles

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

Growth and photosynthetic changes of Ulva prolifera in response to diurnal temperature variations

Growth and photosynthetic changes of Ulva prolifera in response to diurnal temperature variations

Quantitative analysis of diurnal CO2 flux variations above an alkaline playa

AbstractThe alkaline playas at Atlin, BC, provide a unique opportunity for studying the carbonate–bicarbonate system and carbonate mineral stability at the Earth's surface. In this study, dynamic closed chambers (DCCs) and pore‐gas sampling were used to directly quantify carbon dioxide (CO2) emission rates and characterize processes governing the CO2 exchange across the playa‐atmosphere interface. Data were collected at the Atlin site continuously over 27 days in 2020 and 14 days in 2021. Results indicate minimal net exchange of CO2 across the playa‐atmosphere interface during the monitoring periods, with average fluxes over the two periods of −0.03 and 0.09 µmol m−2 s−1 in 2020 and 2021, respectively. However, distinct diurnal oscillations of CO2 fluxes were measured with average daytime fluxes of 0.15 ± 0.34 µmol m−2 s−1 (2020) and 0.15 ± 0.19 µmol m−2 s−1 (2021) and nighttime fluxes of −0.24 ± 0.31 µmol m−2 s−1 (2020) and 0.04 ± 0.18 µmol m−2 s−1 (2021). These observations, supported by reactive transport modeling, indicate that CO2 exchange is predominantly governed by changes in CO2 solubility in alkaline porewater related to diurnal temperature fluctuations and variations in CO2 concentrations in ambient air above the ground surface. Even though CO2 concentrations exceed 8000 ppmv at 1‐m depth, CO2 emissions to the atmosphere were found to be minimal, likely due to high moisture contents, low connectivity, and tortuosity, limiting upward CO2 migration. These findings provide insights into CO2 flux dynamics in alkaline arid regions and show promise for the application of the DCC method for monitoring ex situ carbon mineralization at sites with enhanced mineral weathering.

Cumulative Multi-Day Effect of Ambient Temperature on Thermal Behaviour of Buildings with Different Thermal Masses

In most studies, the effect of the thermal capacity of the building envelope on changes in internal temperatures is reduced to a 24 h period. During this period, daytime heat gains are balanced by nighttime heat losses. The maximum indoor temperature, the diurnal variation of the indoor temperature and the time lag between the occurrence of the maximum daily temperature determine the effect achieved. The aim of the article was to show that the effect of the thermal capacity of a building on the indoor temperature is not limited to 24 h but accumulates over a period of several days, mainly depending on the temperature and solar radiation history of the previous days. As a result, contrary to what some studies have suggested, the bedrooms of heavier buildings remained significantly colder at night during periods of prolonged high outdoor temperatures. The results obtained may fundamentally influence the perception of the effect of using the high thermal capacity of the building envelope to reduce high indoor temperatures in hot weather.

Spatially resolved indoor overheating evaluation using microscale meteorological simulation as input for building simulation – opportunities and limitations

To assess the spatial heat resilience of buildings in urban development we test the suitability of a toolchain approach from microscale meteorological simulations, resolving the spatial influences on local urban climate, to building performance simulations, evaluating the indoor overheating risk in buildings. This approach makes it possible to investigate how much microscale effects (e.g. buildings, trees e.g. roads) in open space influence the overheating intensity in a building depending on its location within a district. In this context, the question arises how realistic the microscale meteorological simulation is to be used as input for indoor overheating evaluation. In this context, we applied a 3D urban climate model (ENVI-met) and a 1D boundary layer model (HIRVAC) for two urban districts in Germany as meteorological input for an indoor thermal comfort evaluation of two representative buildings. The results demonstrate that ENVI-met simulations without using measured temperature data create unrealistically low diurnal variations in outdoor air temperature despite an overestimated solar irradiance. The implementation to building simulation leads to a significant underestimation of the heat resilience for both buildings and to wrong conclusions about the efficacy of passive heat adaptation measures. In contrast, the HIRVACsimulations show a more realistic representation of the meteorological variables (when measured data is used for calibration) but are not able to resolve urban 3D structures. Our findings point out that an adjusted boundary layer representation in microscale meteorological simulations is crucial to provide meteorological input suitable for realistic spatially resolved indoor overheating analysis.

Meteorological Influence on Atrial Fibrillation and Flutter: A Nationwide Observational Study in South Korea (2010-2022).

Background and rationale The impact of meteorological factors, including atmospheric temperature, humidity, and wind speed, on the incidence of atrial fibrillation and flutter (AF) has been the subject of several studies, but the findings have been inconsistent. Given the complex and multifaceted nature of this relationship, a larger-scale study was necessary to provide sufficient statistical power and elucidate potential associations between them. The aim of this study was, thus, to investigate the potential associations between meteorological factors and the incidence of AF. Methods The South Korean government provides open access to national health insurance and weather data for its citizens; the data was available from January 2010 to July 2022. The national health insurance data includes the monthly number of patients diagnosed with a specific condition, reflecting the incidence and prevalence of the condition. Pearson correlation analyses were performed using the statistical analysis software, SAS® OnDemand for Academics (SAS Institute Inc., Cary, North Carolina, United States), to examine the association between each month's national average climate data and the number of patients diagnosed with AF. Results The number of patients diagnosed with AF in the total population showed a statistically significant correlation only with average wind speed (correlation coefficient (r)=-0.42, 95%CI -0.55 to -0.28, p<0.001) and sunshine duration (r=0.27, 95%CI 0.12 to 0.41, p<0.001). Among females aged 20-24 years, there was a statistically significant association with other variables, including average temperature, precipitation, humidity, and atmospheric pressure (p<0.05). Diurnal temperature variation showed inconsistent associations across different age and sex groups. Conclusion The number of patients diagnosed with AF is negatively correlated with average wind speed and positively correlated with sunshine duration in the general population, particularly among the elderly. There was no significant association between the number of patients diagnosed with AF and average temperature, precipitation, or humidity, except for females aged 20-24 years, who exhibited a significant association with these variables. However, it is important to note that these correlations do not establish causality.

Thermal performance of an innovative double-skin ventilated façade with multistep-encapsulated PCM integration

The simultaneous occurrence of nighttime insulation requirements and daytime overheating risks in a single day is a concern of buildings that is often overlooked. This study introduces a novel approach utilizing a dual-phase change materials (DPCM) layer in a double-skin ventilated glazing façade (DSPVGF) to store and release energy through photothermal conversion. This technology facilitates heat removal during the day via a ventilation layer and the reduces long-wave radiation through a vacuum glass layer. The thermal performance of DSPVGF is evaluated under a temperate continental climate characterized by significant diurnal temperature variations. Emphasis is placed on considering the net solar energy gain of DSPVGF. The results demonstrate that DSPVGF outperforms ventilated façades utilizing air or PCM, exhibiting the lowest heat transfer rate of 30.03 W. Optimal DSPVGF configurations for climates with substantial temperature fluctuations are identified, including a DPCM melting temperature of 28 °C and 16 °C, a thickness of 36 mm, and multistep placement by turn according to a height-to-width ratio of 200D. Daytime ventilation with a flow velocity of 1.09 m·s−1 is confirmed as the most effective passive cooling strategy.

Making an urban environmental climate map of the Bangkok Metropolitan Region, Thailand: Analysis of air temperature, wind distributions, and spatial environmental factors

Urban heat islands (UHIs) are a global phenomenon. They are particularly evident in expansive urban centers such as Bangkok, Thailand's capital. Recent research has highlighted the escalation of temperatures and poor ventilation due to severe urbanization. Nevertheless, scant attention has been paid to both temperature and wind distribution. Concurrently, the imperatives of urban development policies require the integration of environmental and climatic factors. In this context, the present study delves into the UHIs in Bangkok and the climatic dynamics within the expansive Bangkok Metropolitan Region (BMR), encompassing six provinces. Utilizing climate data from 68 observation stations in 2019, this study aims to unravel the intricate interplay between air temperature distributions, wind distributions, and spatial environmental factors within the BMR, with the ultimate objective of constructing a comprehensive Urban Environmental Climate Map (UECM) tailored to the BMR. This study comprises three key stages. Initially, the authors classified the spatial-physical attributes of observation points, encompassing variables such as land use and land coverage (LULC). Subsequently, an exhaustive analysis was conducted to delve into the relationship between the climate distributions and spatial environmental factors. The insights lead to a refined UECM that encapsulates the BMR's climatic intricacy. The results of this study yield novel findings. Nocturnal air temperature fluctuations within the BMR exhibited a discernible correlation with green cover and proximity to water resources. Conversely, diurnal temperature variations predominantly hinge on the distance from the coastline in the direction of the sea breeze (DCDS). Moreover, during summer, the diurnal wind speed demonstrated a significant correlation with DCDS and the building coverage. Therefore, the UECM for the BMR was divided into nine distinct zones, each associated with varying degrees of recommendations for LULC and ventilation enhancement. Notably, the priority zones for heat mitigation efforts are mostly located in the central Bangkok. This study has academic implications. It has the capacity to inform and shape governmental policies and urban planning across BMR provinces. Stakeholders aim to gain a better understanding of their environmental milieu. These findings advocate future urban planning by integrating UECMs and design guidelines that consider science and policy. This approach is suitable for sustainable urban development.

Diurnal temperature variation and the implications for diagnosis and infectious disease screening: a population-based study.

Fevers have been used as a marker of disease for hundreds of years and are frequently used for disease screening. However, body temperature varies over the course of a day and across individual characteristics; such variation may limit the detection of febrile episodes complicating the diagnostic process. Our objective was to describe individual variation in diurnal temperature patterns during episodes of febrile activity using millions of recorded temperatures and evaluate the probability of recording a fever by sex and for different age groups. We use timestamped deidentified temperature readings from thermometers across the US to construct illness episodes where continuous periods of activity in a single user included a febrile reading. We model the mean temperature recorded and probability of registering a fever across the course of a day using sinusoidal regression models while accounting for user age and sex. We then estimate the probability of recording a fever by time of day for children, working-age adults, and older adults. We find wide variation in body temperatures over the course of a day and across individual characteristics. Thediurnal temperature pattern differed between men and women, and average temperatures declined forolder age groups. The likelihood of detecting a fever varied widely by the time of day and by an individual's age or sex. Time of day and demographics should be considered when using body temperatures for diagnostic or screening purposes. Our results demonstrate the importance of follow-up thermometry readings if infectious diseases are suspected.

Effects of intrauterine and postnatal exposure to meteorological factors on childhood pneumonia

BackgroundChildhood pneumonia remains a major public health concern worldwide, but the critical meteorological factors that contribute to it are unknown. ObjectiveTo investigate the relationship between childhood pneumonia and prenatal and postnatal exposure to meteorological factors to identify the critical factors and vulnerable timing windows. MethodsWe conducted a retrospective cohort study of 8689 preschoolers in China. We gathered information on personal factors, health status, and indoor environment through questionnaires. We considered meteorological factors including temperature (mean, maximum, minimum), diurnal temperature variation (DTV), relative humidity, wind speed, rainfall, pressure and sunshine during early life. Using multiple logistic regression models, we investigated the links between childhood pneumonia and early life exposure to meteorological factors. ResultsExposure to mean, maximum, and minimum temperatures was associated with childhood pneumonia in the first month and first trimester, with ORs (95% CI) of 1.32 (1.07–1.62), 1.26 (1.04–1.52) and 1.33 (1.08–1.64) in the first month, and 1.42 (1.12–1.81), 1.36 (1.08–1.71) and 1.47 (1.15–1.88) in the first trimester for per IQR increase in each meteorological factor exposure. Wind speed, rainfall, and sunshine exhibited significant associations with pneumonia during the first, second, and third trimesters, respectively. Exposure to various temperatures, DTV, relative humidity, rainfall, air pressure, and sunshine were linked to childhood pneumonia in the postnatal period, particularly in the previous year. The sensitivity analysis revealed that boys are more vulnerable to meteorological factors. Keeping dogs or plants may offer protection against the pneumonia risk of prenatal and postnatal meteorological exposure. ConclusionExposure to meteorological factors during both the prenatal and postnatal periods, especially in early pregnancy, was found to elevate the risk of childhood pneumonia.

Cool, dry nights and short heatwaves during growth result in longer telomeres in temperate songbird nestlings.

Exposure to rising sublethal temperatures can affect development and somatic condition, and thereby Darwinian fitness. In the context of climate warming, these changes could have implications for population viability, but they can be subtle and consequently difficult to quantify. Using telomere length (TL) as a known biomarker of somatic condition in early life, we investigated the impact of pre-hatching and nestling climate on six cohorts of wild nestling superb fairy wrens (Malurus cyaneus) in temperate south-eastern Australia. Models incorporating only climate information from the nestling phase were best supported compared to those including the (pre-)laying to incubation phase (previously shown to affect mass) or both phases combined. This implies that nestling TL is most sensitive to ambient climate in the nestling phase. The top model showed a negative relationship between early-life TL and nestling mean daily minimum temperature when rainfall was low which gradually became positive with increasing rainfall. In addition, there was a positive relationship between TL and the frequency of hot days (daily maximum temperature ≥35°C), although these temperatures were rare and short-term. Including other pre-hatching and nestling period, climate variables (e.g., mean daily maximum temperature and mean diurnal temperature variability) did not improve the prediction of nestling TL. Overall, our results suggest that cooler nights when conditions are dry and short-term temperature spikes above 35°C during development are conducive for somatic maintenance. While these findings indicate a potential pathway for climate warming to impact wildlife fitness, they emphasize the need to elucidate the mechanisms underlying these complex associations.

The Minimum Temperature Outweighed the Maximum Temperature in Determining Plant Growth over the Tibetan Plateau from 1982 to 2017

The Tibetan Plateau (TP) plays a crucial role in the climate change of China as well as global climate change. It is therefore of great practical significance to study vegetation and its dynamic changes for regional ecological protection. The combination of a dry climate and notable temperature disparities can lead to intricate effects on the region’s vegetation. However, there are few studies exploring the complex effects of diurnal temperature variations on vegetation growth that differ from the effects of mean temperature on the TP, especially under different frozen ground types. Based on the long-time series maximum temperature (Tmax), minimum temperature (Tmin), and Normalized Difference Vegetation Index (NDVI) of the TP, we conducted a comparative study of the warming effects on plant growth under different frozen types. The results exhibit that it warms up faster at night (0.223 °C de−1; p &lt; 0.01) than during the day (0.06 °C de−1; p &lt; 0.01), resulting in a significant decrease in the temperature difference between day and night (−0.078 °C de−1; p &lt; 0.01) in the past few decades. The principal finding of this paper is that Tmin is the dominant temperature indicator for vegetation growth on the TP, which dominates 63.3% of the area for NDVI and 61.4% of the area for GPP, respectively. The results further identify a stronger correlation between air temperature and vegetation growth in seasonal frozen grounds (R = 0.68, p &lt; 0.01) and permafrost regions (R = 0.7, p &lt; 0.01) compared to unfrozen grounds (R = 0.58, p &lt; 0.01). Moreover, the physiological mechanism underlying the asymmetric influence of Tmin and Tmax on vegetation growth is further elucidated in this study. Given that future climate changes are expected to exacerbate these changes, it is imperative to explore additional avenues in pursuit of potential mechanisms that can offer adaptive strategies for safeguarding the ecology of the TP.

Spatiotemporally heterogeneous soil thermohydraulic processes in the frozen soil of the Tibetan Plateau

Frozen soil properties and thermohydraulic processes are still not fully understood due to lack of in-situ measurements, especially in the high altitudes and high latitudes (HAHL). Based on hourly measurements at 10, 40, 80 and 120 cm depths at 21 sites in the west, south and northeast regions of the Tibetan Plateau (TP) during July 2018 - July 2019, we examined soil particles, spatiotemporal variations of soil thermohydraulic processes and their connections with environmental factors to reveal the heterogenous frozen soil properties on the TP. Sand and silt are the dominant soil particles and clay is less than 10% at the sites. Existing and widely used soil products underestimates (significantly overestimates) sand (clay) content on the TP which raises the uncertainty in the thermohydraulic parameters derived from these products. Diurnal soil moisture and temperature variations are seen only above 40 cm, but seasonal variations occur down to 120 cm due to the soil memory effect. Seasonally frozen soil and permafrost soil show different freezing and melting processes. Dry soil features greater soil temperature temporal variability and deeper maximum frozen depth than wet soil. Zero curtain occurs in both dry and wet soil, and displays high (low) frequency but short (long) duration at 10 (80) cm that vary spatially. Moisture depression exists in seasonally frozen soil and is determined by the initial soil moisture and temperature gradient strength. The strong thermohydraulic coupling existed in cold season collapses in warm season. Soil moisture exhibits higher spatiotemporal variability than soil temperature. At daily time scale, the influences of precipitation, wind speed and relative humidity on soil moisture and temperature vary under different climate conditions. These findings fill the knowledge gaps in the soil thermohydraulic processes in the HAHL, and improve the understanding of frozen soil properties and heat-water coupling processes in soil in the HAHL. The study will benefit the Earth system model development and improve the quality of soil temperature and moisture assimilation and remote sensing products in the HAHL.

The role of meteorological parameters on childhood asthma: Identifying critical windows of susceptibility during pregnancy

BackgroundDespite numerous studies demonstrating a link between asthma and meteorological parameters, the role of maternal exposure in pregnancy on childhood asthma remains unknown. ObjectiveTo investigate the association of meteorological factors during pregnancy with childhood asthma and identify key exposure windows. MethodsIn central China's Changsha city, we carried out a retrospective cohort study involving 8,689 preschoolers. We used questionnaires to collect information about childhood health, personal factors, socioeconomic status (SES), and indoor environment. We considered meteorological parameters including temperature (mean, maximum, minimum), diurnal temperature variation (DTV), relative humidity, wind speed (mean, extreme), rainfall, pressure, and sunshine during early life. We investigated the links between childhood asthma and meteorological factors using logistic regression models. ResultsDoctor-diagnosed asthma (D-DA) in preschoolers was associated with exposure to increased temperatures (mean, maximum, and minimum) by per IQR increment in the first month with ORs (95% CI) of 2.03 (1.21–3.40), 1.86 (1.15–3.00) and 2.08 (1.23–3.50) as well as in the first trimester with ORs of 2.40 (1.36–4.24), 2.20 (1.26–3.83) and 2.54 (1.43–4.53), respectively. D-DA was inversely related to wind speed in the first month and first two trimesters. Compared to an increased risk of D-DA when exposed to pressure in the third trimester, exposure to DTV during pregnancy, particularly in the third trimester, significantly decreased the risk. Some preschoolers with certain personal factors and high SES were more vulnerable to pre-natal meteorological exposure. ConclusionPrenatal exposure to meteorological factors, especially high temperatures and low wind speeds in early pregnancy, contributes to childhood asthma.

Estimation of the relationship between meteorological factors and measles using spatiotemporal Bayesian model in Shandong Province, China

BackgroundMeasles-containing vaccine (MCV) has been effective in controlling the spread of measles. Some countries have declared measles elimination. But recently years, the number of cases worldwide has increased, posing a challenge to the global goal of measles eradication. This study estimated the relationship between meteorological factors and measles using spatiotemporal Bayesian model, aiming to provide scientific evidence for public health policy to eliminate measles.MethodsDescriptive statistical analysis was performed on monthly data of measles and meteorological variables in 136 counties of Shandong Province from 2009 to 2017. Spatiotemporal Bayesian model was used to estimate the effects of meteorological factors on measles, and to evaluate measles risk areas at county level. Case population was divided into multiple subgroups according to gender, age and occupation. The effects of meteorological factors on measles in subgroups were compared.ResultsSpecific meteorological conditions increased the risk of measles, including lower relative humidity, temperature, and atmospheric pressure; higher wind velocity, sunshine duration, and diurnal temperature variation. Taking lowest value (Q1) as reference, RR (95%CI) for higher temperatures (Q2–Q4) were 0.79 (0.69–0.91), 0.54 (0.44–0.65), and 0.48 (0.38–0.61), respectively; RR (95%CI) for higher relative humidity (Q2–Q4) were 0.76 (0.66–0.88), 0.56 (0.47–0.67), and 0.49 (0.38–0.63), respectively; RR (95%CI) for higher wind velocity (Q2–Q4) were 1.43 (1.25–1.64), 1.85 (1.57–2.18), 2.00 (1.59–2.52), respectively. 22 medium-to-high risk counties were identified, mainly in northwestern, southwestern and central Shandong Province. The trend was basically same in the effects of meteorological factors on measles in subgroups, but the magnitude of the effects was different.ConclusionsMeteorological factors have an important impact on measles. It is crucial to integrate these factors into public health policies for measles prevention and control in China.

Impact of ambient temperature on adverse pregnancy outcomes: a birth cohort study in Fuzhou, China.

Previous studies have identified a series of specific adverse pregnancy outcomes (APOs) linked with temperature extremes. Most of them focus on preterm birth, low birth weight, and stillbirth. Other possible adverse outcomes were under-researched. This study aimed to investigate the impact of ambient temperature on maternal complications, white blood cell count (WBC), newborn hearing, and neonatal jaundice. A total of 418 participants were recruited from Fuzhou Maternity & Child Healthcare Hospital in 2016. Participants were invited to fill out a structured questionnaire. The gridded near-surface air temperatures at a resolution of 0.1°* 0.1° for Fuzhou were extracted from a published dataset. Meteorological data and PM2.5 were extracted based on participants' residential addresses using R packages "ncdf4" and "raster." Multivariate logistic regression models were used to quantify the effects of ambient temperature on APOs after controlling for confounders. Overall, there were 107 APOs, accounting for 25.6% of all participants. Every 1°C increase in mean temperature was associated with a 10.0% increase in APOs (aOR = 1.100, 95%CI 1.006-1.203) during the period of early pregnancy. However, negative associations were observed in the middle pregnancy period, and a 1°C increase in mean temperature was associated 8.8% decrease in APOs (aOR = 0.912, 95%CI 0.846-0.982). Diurnal temperature variation had a significant impact on APOs in the third trimester. Infant jaundice was negatively associated with temperature exposure in the middle and late pregnancy periods. The risk of neonatal jaundice increased at lag weeks 2-9 in the first trimester, with the greatest lagged effect (aOR = 1.201, 95%CI 1.020-1.413) observed at lag week 3. A 1°C increase in mean temperature led to a 29.6% (aOR = 1.296, 95%CI 1.019-1.649) increase in high WBC. A 1°C increase in temperature variation was associated with more than two times (aOR = 2.469, 95%CI 1.001-6.089) increase of high WBC in the first trimester and about five times (aOR = 4.724, 95%CI 1.548-14.409) increase in the third trimester. Ambient temperature affects neonatal jaundice, newborn hearing loss, and infections during pregnancy. In addition to the identified epidemiologic link and susceptible exposure windows, there is a need to understand the underlying biological mechanisms for better recommendations for climate change adaptation policies.