Average Daily Maximum Temperature Research Articles

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.

Effects of dispersed and aggregated retention on epiphytic microarthropod assemblages: A northern hardwood forest case study

Epiphytic lichens and bryophytes provide important habitat for microarthropods, yet little work has documented epiphytic microarthropod assemblages. Further, the response of epiphytes and their associated microarthropod communities to varying levels of forest disturbance and cutting intensity are not well known. We conducted a case study to provide an initial community description of epiphyte-dwelling microarthropods in Adirondack northern hardwoods, and to assess potential for impacts of aggregated and dispersed patterns of reserve tree retention to these communities. In total, 79 families of microarthropods were identified in the 0.14 m2 of samples. Late summer average daily maximum temperatures were 3.2 °C higher in the shelterwood, and three years following treatments the per-unit area dry weight of the bole-associated bryophyte Neckera pennata was 34 % lower in the shelterwood. Microarthropod richness and density were distinctly greater in epiphyte substrates at the base of trees, and were reduced in the shelterwood. Several indicator taxa were identified within the basal bryophytes in the reserve treatment, and in both bryophytes the microarthropod assemblages were more homogenous in the shelterwood. A few mobile and heavily sclerotized taxa persisted in shelterwood substrates, especially in the lichens which lacked 3-dimensional structure. This case study revealed a diverse community of microarthropods in northern hardwood forests that were structured by epiphyte type, height on tree and, potentially, by canopy removal, and suggests conservation value of aggregated tree retention when applying even-age regeneration methods with respect to epiphytic bryophytes, lichens, and their associated invertebrates.

Efficacy assessment of green-blue nature-based solutions against environmental heat mitigation

Nature-based solutions (NBS) such as green (vegetation) and blue (waterbodies) infrastructure are being promoted as cost-effective and sustainable strategies for managing the heatwaves risks, but long-term monitoring evidence is needed to support their implementation. This work aims to conduct a comparative assessment of the cooling efficiency of green (woodland and grassland) and blue (waterbody) NBS in contrast to a built-up area. Over a year of continuous fixed monitoring showed that the average daily maximum temperatures at NBS locations were 2–3 °C (up-to 15%) lower than the built-up area. Woodland showed the maximum temperature reduction in almost all seasons, followed by waterbody and grassland. NBS performed the best during the summers, peak sunshine, and heatwave hours (up to ∼ 6 °C cooler than built-up area). Using an e-bike for mobile monitoring, the areas where green–blue NBS were combined showed the highest spatial cooling extent, followed by waterbody, woodland, and grassland areas. The database generated can validate city-scale environmental models and assist city planners to incorporate NBS into urban dwellings based on the opportunity, need and scope, aligning with Sustainable Development Goals 11 (sustainable cities and communities) and 13 (climate action).

Local weather affects body condition of three North American songbird species on the Texas Coast.

Body condition is a frequently used physiological indicator of avian health and can be affected by an array of environmental variables. Although a number of studies have investigated the specific effects of individual weather variables on body condition in birds, few have analyzed the effects of both temperature and precipitation within the context of an extreme weather event such as hurricanes. In this study, we examined the relationship between breeding-season body condition and daily maximum temperature, daily minimum temperature, and monthly total precipitation for three passerine bird species at the Welder Wildlife Refuge near Rockport, Texas. We also evaluated yearly changes in body condition over a 12-year period for northern cardinals (Cardinalis cardinalis), painted buntings (Passerina ciris), and white-eyed vireos (Vireo griseus), focusing on the extreme precipitation event of Hurricane Harvey, which caused heavy localized flooding. We found that body condition declined with average daily minimum and maximum temperatures, while precipitation had varied, species-specific effects in the three species analyzed. Our results also suggest that northern cardinals experienced a notable reduction in average body condition in the 2 years following Hurricane Harvey. Taken together, we conclude that short-term precipitation and temperature drivers can be important correlates of body condition in songbirds and that severe weather events may reduce body condition in some bird species.

TEMPERATURE AND PRECIPITATION REGIME IMPACT ON SPRING BARLEY (HORDEUM VULGARE) GROWTH IN PRIEKUĻI CASE

In Latvia, the effects of drought and extreme temperatures on spring barley have so far been little studied due to the availability of data and the fact that meteorological conditions are only one of the multi-influencing factors that affect the agricultural sector.Barley usually flowers before or at the same time as ear emergence. During the flowering period high ambient temperatures are critical for yield formation. If the air temperature during flowering is above 22℃ the flowers of spring barley become sterile. From 2004 - 2022, a significant and positive correlation (R = 0,57) was observed between the average maximum daily temperature from sowing to ear emergence and the number of empty flowers in the main spike. A significant negative correlation (R = 0,55) was observed between plant height and the sum of precipitation from sowing to ear emergence and spike length and the sum of precipitation from ear emergence to maturity (R = −0,54), drought also negatively affects tillering rate and number of productive stems per plant.The combination of all the above-mentioned conditions significantly impacts the yield of barley. The following and relevant findings are very important for the agricultural sector, especially in the context of climate change.

Sunshine and Temperature Based Models for Estimating Global Solar Radiation in Maiduguri, Nigeria

Nine existing sunshine based models and three existing temperature based models were evaluated and compared to ascertain the most suitable models for estimating global solar radiation in Maiduguri; the most suitable sunshine based and most suitable temperature based models were also compared. The measured monthly average daily global solar radiation, sunshine hours, maximum and minimum temperature meteorological parameters during the period of thirty one years (1980 – 2010) was utilized and the evaluated models were tested statistically using validation indicators of coefficient of determination, Mean Bias Error, Root Mean Square Error, Mean Percentage Error, t – test, Nash – Sutcliffe Equation and Index of Agreement. The results indicated that the linear exponential sunshine based model and the logarithmic temperature based model were found more accurate for global solar radiation estimation in Maiduguri as compared to other evaluated models. Furthermore, the logarithmic temperature based model was found more accurate for estimating global solar radiation as compared to the linear exponential sunshine based model, and this was testified from the figure showing the comparison between the recommended sunshine based and temperature based models in which the recommended temperature based model depicts the best fitting with the measured global solar radiation data.

Influence of terrain and atmospheric boundary layer on the ventilation and thermal comfort performance of windcatchers

Windcatchers are a promising natural ventilation alternative to conventional ventilation systems. In recent years, many studies attempted to address the different gaps in the field but the impact of terrain type on the performance of windcatchers is still an unexplored topic. Therefore, this paper investigates how the windcatcher's ventilation performance and thermal comfort are affected by different types of terrain and atmospheric boundary layer (ABL) profiles. To reach this goal, numerical simulations were employed and validated against experimental data. The performance was assessed in four terrain types (open, rough, suburban and urban) and two thermal scenarios (outdoor temperatures of 21.5 °C as the Nottingham's average maximum daily temperature for July and 26 °C as the summer design temperature). As the terrain changes from a more uniform open countryside to a less uniform urban region, the induced flow rate decreases from 1040 L/s to 690 L/s, which still surpasses the values of 160 L/s and 94 L/s recommended by the CIBSE and ASHRAE 62.1 standards. The maximum mean age of air (MAA) at the breathing height of a seated person reaches the value of 173 s and 190 s for suburban and urban regions while it does not exceed 140 s for open and rough country. Thermal comfort was assessed based on PMV and the adaptive model. The results showed that in the 1st thermal scenario (at an outdoor temperature of 21.5 °C), all terrains are within the adaptive comfort band. However, PMV was out of the comfort range in nearly 50% of the seated head height plane. However, in 2nd scenario (outdoor temperature of 26 °C), all terrains failed to provide comfort. Furthermore, the urban cases showed higher temperatures and PMV in both scenarios.

Weather Patterns and the Frequency of Ophthalmology Consultations in the Emergency Setting

ABSTRACT Purpose To determine if weather patterns are associated with the frequency of ophthalmology consultations in the Emergency Room (ER) and trauma settings. Methods Hospital-based ophthalmology consultations between January 1, 2015 and December 31, 2020 at the University of Maryland Medical Center (UMMC) were included in the BALCITE (BALtimore Consultation, Inpatient, and Trauma of the Eye) database. Encounters were filtered to the general ER, the R. Crowley Adams Shock Trauma Center, and consultations within 24 h of admission where a delay was attributed to bed assignment. Weather data from the National Climatic Data Center (NCDC) for Baltimore, Maryland, was matched to the day of the initial encounter. Results A total of 3,877 patients were included. Overall, there was a significant association between increasing daily average temperature (R 2 = .152, p = 0.0003) and daily maximum temperature (R 2 = .243, p < 0.001) with incidence of ophthalmology consultations. There was no significant decrease in consultations with increasing precipitation (R 2 = −.007, p = 0.7477). For trauma-related consultations, there was not a significant association between consultation incidence and average daily temperature (R 2 = .011, p = 0.2013), maximum daily temperature (R 2 = −0.012, p = 0.6529), or precipitation levels (R 2 = .075, p = 0.24). The months with the highest consultation volume were September, August, and July, and the lowest numbers in April, March, and February. Conclusions Emergency ophthalmology consultations increased with increasing daily temperature. Trauma-specific consultations did not show a significant association with weather patterns. This information may prove useful to ER providers and ophthalmologists in order to help predict frequency of consultations and better deploy personnel and resources.

Analysis of Seismic Impact on Hailuogou Glacier after the 2022 Luding Ms 6.8 Earthquake, China, Using SAR Offset Tracking Technology

An Ms 6.8 earthquake struck Luding County, Ganzi Prefecture, Sichuan Province on 5 September 2022, with the epicenter about 10 km away from Hailuogou Glacier. How Hailuogou Glacier was affected by the earthquake was of major concern to society. Sentinel-1 SAR satellite imaging was used to monitor the glacier surface velocity during different periods before and after the Luding earthquake based on pixel offset tracking (POT) technology, which applies a feature-tracking algorithm to overcome the phase co-registration problems commonly encountered in large displacement monitoring. The results indicated that the velocity had a positive correlation with the average daily maximum temperature and the slope gradient on the small-slope surfaces. The correlation was not apparent on the steeper surfaces, which corresponded spatially with the identified ice avalanche region in the Planet images. It was deduced that this may be because of the occurrence of ice avalanches on surfaces steeper than 25°, or that the narrower front channel impeded the glacier’s movement. The Luding earthquake did not cause a significant increase in the velocity of Hailuogou Glacier within a large range, but it disturbed the front area of the ice cascade, where the maximum velocity reached 2.5 m/d. Although the possibility of directly-induced destruction by ice avalanches after the earthquake was low, and the buffering in the downstream glacier tongue further reduced the risk of ice avalanches, the risk of some secondary hazards such as debris flow increased. The proposed method in this study might be the most efficient in monitoring and evaluating the effects of strong earthquakes on glaciers because it would not be limited by undesirable weather or traffic blockage.

Variability and assessment of interrelationships among yield and yield-related characters of pea accessions under the influence of high temperature

ABSTRACT Understanding the response and variability of pea accessions traits to high temperatures is an excellent strategy for breeding pea for heat tolerance. This research aimed to determine character variability and interrelationships among yield and yield-related traits as responses to pea grown under daily high temperature. Ninety-four pea accessions were grown under greenhouse conditions in Malaysia and Indonesia in the 2020–2021 season. During flowering up to the physiological maturity stage, the average daily maximum temperature was 31.6°C–32.4°C in Malaysia and 26.5°C–27.6°C in Indonesia. Heat stress reduced grain yield in Malaysia by 40% when the daily maximum temperature was above 32°C compared to yield in Indonesia. The number of seeds per pod, number of seeds per plant, filled pods per plant and number of ovules per pod were positively correlated with grain yield in Malaysia and Indonesia, respectively. A negative correlation was observed for percent aborted flower and aborted seed with grain yield. The genotype by trait biplot identified accessions B32, A19, G76, A11 and D44 as potentially promising under high-temperature conditions with high yield supported by plant height.

Life-history characteristics and climate correlates of dioecious plant species in central southern Australia

Context The proportion of dioecious species can vary considerably among climates and habitats. However, studies often involve isolated communities or large diverse areas and fail to capture how proportions vary across diverse landscapes.Aims To identify (1) life-history associations of terrestrial dioecious plant species in central southern Australia, (2) whether proportion of dioecy varies spatially across central southern Australia, and (3) whether proportion of dioecy is correlated with life-history and/or climate factors.Methods Species growth form, pollination mechanisms and seed-dispersal features were extracted from herbarium databases to determine potential dioecy-linked traits. Distribution data for native terrestrial species in 66 Interim Biogeographical Regionalisation of Australia subregions were extracted from the Australasian Virtual Herbarium to calculate the proportion of total native species richness that are dioecious. Climate data for each subregion were also obtained from Terrestrial Ecology Research Network databases to investigate relationships among climate, life-history traits and dioecy.Key results Woodiness, abiotic pollination and endozoochory were more prevalent in dioecious than non-dioecious taxa. Proportion of dioecy ranged from 1.7% to 8.5% among subregions and correlated negatively with annual temperature range, January to March rainfall and precipitation seasonality and with average annual daily mean, minimum, maximum and average annual minimum temperature. The highest-ranked models of dioecy incorporated the additive effects of the relative proportion of woody species and either annual temperature ranges, January to March rainfall or average annual daily maximum temperature.Conclusions Dioecy was associated with woodiness, abiotic pollination and endozoochory, in line with studies of other flora, with the model of stable temperature range and woodiness being the highest-ranked model of dioecy.Implications Areas with higher proportions of dioecy can be targeted for future investigations into dioecious plant ecology to aid conservation and ecosystem management.

Influence of high temperatures on Post-COVID-19 conditions

Patients with chronic diseases are especially vulnerable on hot days because high temperatures lead to exacerbation of a number of cardiovascular, neurological, autoimmune, and other chronic diseases. Acute SARS-CoV-2 infection has left tens of thousands of Bulgarians suffering from a new chronic disease: Post COVID-19 syndrome. The Bulgarian Cardiac Institute, in trend with innovations, has launched the first worldwide study to establish the relationship between high ambient temperatures and Post COVID-19 conditions. It covers 1310 citizens and was held during the hottest month in history - July 2021. Eight districts in Bulgaria are covered, and for each of them, we calculated a number of meteorological parameters and determined their influence on the persistent signs and symptoms. Shumen District is the district with the highest percentage of citizens with peristaltic complaints (86%) and the most pronounced in terms of severity. This is the area with the lowest average daily maximum temperature (28.44º), the highest average night minimum temperature (20.42º), and the lowest average temperature amplitude (8.02º) for July 2021. It is characteristic that the neurological symptoms (dizziness, headache, impaired concentration, and memory) are predominant at a lower temperature amplitude (Shumen district). Symptoms of the cardiovascular system (shortness of breath, fatigue, palpitations, chest pain) are more commonly reported at higher temperature amplitudes (Pleven district). The results of the study show that high values ​​of ambient temperatures affect Post COVID-19 conditions. The most unfavorable effect is exerted by the high average night minimum temperatures and the small temperature amplitude. Cardiovascular symptoms are particularly pronounced at large temperature amplitudes and neurological at small temperature amplitudes. Post-COVID-19 conditions are unpredictable and patient care continues during the hot months.

Effects of long-term average temperature on cardiovascular disease hospitalizations in an American elderly population

BackgroundShort-term exposure to high or low temperatures is associated with increased mortality and morbidity. Less is known about effects of long-term exposure to high or low temperatures. Prolonged exposure to high or low temperatures might contribute to pathophysiological mechanisms, thereby influencing the development of diseases. Our aim was to evaluate associations of long-term temperature exposure with cardiovascular disease (CVD) hospitalizations. MethodsWe constructed an open cohort consisting of all fee-for-service Medicare beneficiaries, aged ≥65, living in the contiguous US from 2000 through 2016 (∼61.6 million individuals). We used data from the 4 km Gridded Surface Meteorological dataset to assess the summer (June–August) and winter (December–February) average daily maximum temperature for each year for each zip code. Cox-equivalent Poisson models were used to estimate associations with first CVD hospitalization, after adjustment for potential confounders. We performed stratified analyses to assess potential effect modification by sex, age, race, Medicaid eligibility and relative humidity. ResultsHigher summer average and lower winter average temperatures were associated with an increased risk of CVD hospitalization. We found a HR of 1.068 (95% CI: 1.063, 1.074) per IQR increase (5.2 °C) for summer average temperature and a HR of 1.022 (95% CI: 1.017, 1.028) per IQR decrease (11.7 °C) for winter average temperature. Positive associations of higher summer average temperatures were strongest for individuals aged <75 years, Medicaid eligible, and White individuals. Positive associations of lower winter average temperatures were strongest for individuals aged <75 years and Black individuals, and individuals living in low relative humidity areas. ConclusionsLiving in areas with high summer average temperatures or low winter average temperatures could increase the risk of CVD hospitalizations. The magnitude of the associations of summer and winter average temperatures differs by demographics and relative humidity levels.

Varying Responses of Vegetation Greenness to the Diurnal Warming across the Global.

The distribution of global warming has been varying both diurnally and seasonally. Little is known about the spatiotemporal variations in the relationships between vegetation greenness and day- and night-time warming during the last decades. We investigated the global inter- and intra-annual responses of vegetation greenness to the diurnal asymmetric warming during the period of 1982–2015, using the normalized different vegetation index (NDVI, a robust proxy for vegetation greenness) obtained from the NOAA/AVHRR NDVI GIMMS3g dataset and the monthly average daily maximum (Tmax) and minimum temperature (Tmin) obtained from the gridded Climate Research Unit, University of East Anglia. Several findings were obtained: (1) The strength of the relationship between vegetation greenness and the diurnal temperature varied on inter-annual and seasonal timescales, indicating generally weakening warming effects on the vegetation activity across the global. (2) The decline in vegetation response to Tmax occurred mainly in the mid-latitudes of the world and in the high latitudes of the northern hemisphere, whereas the decline in the vegetation response to Tmin primarily concentrated in low latitudes. The percentage of areas with a significantly negative trend in the partial correlation coefficient between vegetation greenness and diurnal temperature was greater than that of the areas showing the significant positive trend. (3) The trends in the correlation between vegetation greenness and diurnal warming showed a complex spatial pattern: the majority of the study areas had undergone a significant declining strength in the vegetation greenness response to Tmax in all seasons and to Tmin in seasons except autumn. These findings are expected to have important implications for studying the diurnal asymmetry warming and its effect on the terrestrial ecosystem.

Correlation of Pollen Concentration and Meteorological Factors with Medical Condition of Allergic Rhinitis in Shenyang Area.

Background The pathogenesis of allergic rhinitis (AR) was affected by meteorological and environmental factors. This study investigated the association between clinical symptoms of AR patients with pollen dispersal and meteorological conditions. Methods The clinical features of 10,838 AR patients who were treated in the Department of Otorhinolaryngology, The First Hospital of China Medical University, Shenyang, from March 2021 to October 2021 were retrospectively analyzed. We collected pollen by a pollen collector, read and counted it under a microscope, identified the species of the pollen particles, and recorded meteorological data (average daily temperature, maximum and minimum temperature, average daily wind, average daily precipitation, average daily humidity, average pressure, air quality index, PM2.5, PM10, SO2, NO2, CO, and O3), to analyze the correlation among meteorological conditions, pollen dispersal, and number of AR visits. Finally, pollen allergen-positive and symptoms were scored. Results Among the AR visits, patients >41 years old accounted for the highest proportion (64.15%). 43.67% of the patients were complicated with bronchial asthma, and the disease incidence peaked in September. During the period of the study, a total of 27,512 pollen grains were collected, and 17 species were identified. The pollens of Compositae and Moraceae were the main allergenic sources leading to the increase in AR visits from August to September. The peak of pollen dispersal was in spring, summer, and autumn. The total amount of pollen was not only related to the average daily minimum temperature, average daily precipitation, and average daily humidity but also had a significant correlation with air quality index and air pollutants (PM2.5 and PM10, SO2, NO2, and CO). In addition, there was a significant correlation between the number of daily pollen allergen-positive patients and the pollen concentration of Compositae and Moraceae as well as air pollution components. The clinical symptoms of pollen allergen-positive patients were mainly nasal congestion, red/itchy eyes, and epiphora. Conclusion The peak seasons of pollen dispersal in Shenyang were in spring, summer, and autumn, and the allergenic pollens were mainly Compositae and Moraceae. In addition, AR was substantially correlated with pollen concentration and meteorological factors. This study may help provide early warning information and prevention for AR patients.

Future projections of extreme temperature events in Southwest China using nine models in CMIP6

Southwest China, which is close to the Qinghai-Tibet Plateau, presents complex topography. As a result of the combined influence of the South Asian monsoon, East Asian monsoon, and plateau monsoon, climate in this region is unique. Since Southwest China is one of the areas where extreme weather events occur more frequently, this region is sensitive and vulnerable to climate change. In the present research, daily temperature from 1969 to 2020 recorded at 93 weather stations in Southwest China, and data from nine models for the period 1995 to 2040 were used in CMIP6 (Coupled Model Intercomparison Project Phase 6) to calculate 17 ETIs (Extreme Temperature Indices). Furthermore, we analyzed and compared the annual change rate, temporal and spatial change trend, and mean change of extreme temperature events in Southwest China and four subzones during historical period and under SSP2-4.5 scenario for the next 20 years. The results showed: 1) The 8 ECTIs (Extreme Cold Temperature Indices) and the 8 EWTIs (Extreme Warm Temperature Indices) in 1969–2020 were corroborated. These results indicated a warming trend. Also, DTR (Diurnal temperature range) showed a decreasing trend, and different degrees of warming were observed in the four subzones. 2) From 2021 to 2040 and under the SSP2-4.5 scenario, the annual rates of change for 17 ETIs in Southwest China showed that extreme cold events will continue to decrease. On the other hand, extreme warm events will continue to increase. 3) Under the SSP2-4.5 scenario in the next 20 years, CSDI (cold spell duration indicator) will decrease, while WSDI (warm spell duration indicator), TMINmean (average daily minimum temperature), and TMAXmean (average daily maximum temperature) will increase. Moreover, the decrease in amplitude of CSDI was smaller than the increase in amplitude of WSDI. Also, the increase in amplitude of TMINmean was slightly smaller than that of TMAXmean. The projected WSDI, TMINmean, and TMAXmean obtained with the preferred three models and MEM-9 (nine-Model Ensemble Mean) showed an overall growing trend with respect to space; however, the increased range fluctuated in different regions. 4) In 2021–2040, mean values of 4 ETIs in different subzones indicated that the lowest TMINmean and TMAXmean were observed in the ZP (Zoigê Plateau), the highest in the YGP (Yunnan-Guizhou Plateau), and intermediate higher in the SB (Sichuan Basin). Compared with the 4 ETI mean values corresponding to 1969–2020, the persistence and average state of extreme cold and warm events in different subzones showed that future change trends depend on altitude.

Unprecedented Heatwave in Western North America during Late June of 2021: Roles of Atmospheric Circulation and Global Warming

An extraordinary and unprecedented heatwave swept across western North America (i.e., the Pacific Northwest) in late June of 2021, resulting in hundreds of deaths, a massive die-off of sea creatures off the coast, and horrific wildfires. Here, we use observational data to find the atmospheric circulation variabilities of the North Pacific and Arctic-Pacific-Canada patterns that co-occurred with the development and mature phases of the heatwave, as well as the North America pattern, which coincided with the decaying and eastward movement of the heatwave. Climate models from the Coupled Model Intercomparison Project (Phase 6) are not designed to simulate a particular heatwave event like this one. Still, models show that greenhouse gases are the main reason for the long-term increase of average daily maximum temperature in western North America in the past and future.

Associations Between Ambient Temperature and Circulating Maternal One-carbon and Amino Acid Metabolites in Pregnancy

ObjectivesExcessive ambient temperature closely linked to climate change is an imminent threat to the health of mothers and children globally. Recent studies have shown detrimental associations between high temperatures during pregnancy and birth outcomes. The goal of this study was to examine relationships between circulating metabolites in the mother and environmental temperature in a resource-limited setting. MethodsThe study was a secondary analysis employing data from the Women First (WF) trial conduced in Thatta, Pakistan. As part of the trial, women of child-bearing age either consumed a comprehensive maternal nutritional supplement (MNS) prior to conception until delivery (Arm 1), from 12 wk gestation until delivery (Arm 2); or were not supplemented with MNS Arm 3. Daily maximum air temperatures were acquired from the closest surface observation systems (n = 131). Average daily maximum temperatures (Tmax) for a 90-day window representing the 1st trimester of pregnancy was calculated for each participant. The number of days in this period when the Tmax was > 39°C was computed to assess ‘heat stress days’. Maternal blood was collected on dried blood spot (DBS) cards at 34 wk gestation. A targeted metabolomics assay measuring concentrations of 23 metabolites was performed on DBS samples using LC-MS/MS. ResultsLinear regression was employed to assess the associations between ambient temperature in the 1st trimester and metabolite levels (z-scores). Models were adjusted for MNS supplementation. Significant associations between Tmax in the 1st trimester and 7 metabolites were observed (FDR p-values < 0.05). Of these, maternal choline concentrations were negatively correlated with maximal temperature in the 1st trimester (β = –0.063, p = 4.3e-10). Concentrations of glutamine, histidine, arginine, symmetrical-dimethylarginine, methionine and cysteine were positively associated (p < 0.05) with daily maximal temperature. ConclusionsCollectively, the findings indicate that exposure to excessive heat stress in the first trimester is associated with lower choline levels and other metabolites important in blood pressure regulation. While the findings are associative, our results point to underlying mechanistic alterations in maternal circulation in concert with environmental heat stress. Funding SourcesBill & Melinda Gates Foundation; NIH/NICHD/ODS.

Assessing climate change impacts on Pacific salmon and trout using bioenergetics and spatiotemporal explicit river temperature predictions under varying riparian conditions.

Pacific salmon and trout populations are affected by timber harvest, the removal and alteration of riparian vegetation, and the resulting physical changes to water quality, temperature, and associated delivery of high-quality terrestrial prey. Juvenile salmon and trout growth, a key predictor of survival, is poorly understood in the context of current and future (climate-change mediated) conditions, with resource managers needing information on how land use will impact future river conditions for these commercially and culturally important species. We used the Heat Source water temperature modeling framework to develop a spatiotemporal model to assess how riparian canopy and vegetation preservation and addition could influence river temperatures under future climate predictions in a coastal river fed by a moraine-dammed lake: the Quinault River in Washington State. The model predicted higher water temperatures under future carbon emission projections, representative concentration pathway (RCP) 4.5 and 8.5, with varying magnitude based on different riparian vegetation scenarios. We used the daily average temperature output from these scenarios to predict potential juvenile fish growth using the Wisconsin bioenergetics model. A combination of riparian vegetation removal and continued high carbon emissions resulted in a predicted seven-day average daily maximum temperature (7DADM) increase of 1.7°C in the lower river by 2080; increases in riparian shading mitigate this 7DADM increase to only 0.9°C. Under the current thermal regime, bioenergetics modeling predicts juvenile fish lose weight in the lower river; this loss of potential growth worsens by an average of 20–83% in the lower river by 2080, increasing with the loss of riparian shading. This study assess the impact of riparian vegetation management on future thermal habitat for Pacific salmon and trout under warming climates and provide a useful spatially explicit modeling framework that managers can use to make decisions regarding riparian vegetation management and its mechanistic impact to water temperature and rearing juvenile fish.

Heat Acclimation with or without Normobaric Hypoxia Exposure Leads to Similar Improvements in Endurance Performance in the Heat.

Background: Combining the key adaptation of plasma volume (PV) expansion with synergistic physiological effects of other acclimation interventions to maximise endurance performance in the heat has potential. The current study investigated the effects of heat acclimation alone (H), combined with normobaric hypoxia exposure (H+NH), on endurance athletic performance. Methods: Well-trained participants completed a heat-stress trial (30 °C, 80% relative humidity (RH), 20.8% fraction of inspired oxygen (FiO2)) of a 75 min steady-state cycling (fixed workload) and a subsequent 15 min cycling time trial for distance before and after intervention. Participants completed 12 consecutive indoor training days with either heat acclimation (H; 60 min·day−1, 30 °C, 80% RH; 20.8% FiO2) or heat acclimation and overnight hypoxic environment (H+NH; ~12 h, 60% RH; 16% FiO2 simulating altitude of ~2500 m). Control (CON) group trained outdoors with average maximum daily temperature of 16.5 °C and 60% RH. Results: Both H and H+NH significantly improved time trial cycling distance by ~5.5% compared to CON, with no difference between environmental exposures. PV increased (+3.8%) and decreased (−4.1%) following H and H+NH, respectively, whereas haemoglobin concentration decreased (−2%) and increased (+3%) in H and H+NH, respectively. Conclusion: Our results show that despite contrasting physiological adaptations to different environmental acclimation protocols, heat acclimation with or without hypoxic exposure demonstrated similar improvements in short-duration exercise performance in a hot environment.