scholarly journals The Heat Strain of Various Athletic Surfaces: A Comparison Between Observed and Modeled Wet-Bulb Globe Temperatures

2017 ◽  
Vol 52 (11) ◽  
pp. 1056-1064 ◽  
Author(s):  
J. Luke Pryor ◽  
Riana R. Pryor ◽  
Andrew Grundstein ◽  
Douglas J. Casa
Keyword(s):  
Environmental Conditions ◽  
Weather Conditions ◽  
Weather Data ◽  
Measurement Variability ◽  
Wet Bulb Globe Temperature ◽  
Athletic Fields ◽  
The Difference ◽  
National Athletic Trainers Association ◽  
Globe Temperature ◽  
Starting Location

Context:  The National Athletic Trainers' Association recommends using onsite wet-bulb globe temperature (WBGT) measurement to determine whether to modify or cancel physical activity. However, not all practitioners do so and instead they may rely on the National Weather Service (NWS) to monitor weather conditions. Objective:  To compare regional NWS WBGT estimates with local athletic-surface readings and compare WBGT measurements among various local athletic surfaces. Design:  Observational study. Setting:  Athletic fields. Main Outcome Measure(s):  Measurements from 2 identical WBGT devices were averaged on 10 athletic surfaces within an NWS station reporting radius. Athletic surfaces consisted of red and black all-weather tracks (track), blue and black hard tennis courts (tennis), nylon-knit artificial green turf, green synthetic turfgrass, volleyball sand, softball clay, natural grass (grass), and a natural lake (water). Measurements (n = 143 data pairs) were taken over 18 days (May through September) between 1 pm and 4:30 pm in direct sunlight 1.2 m above ground. The starting location was counterbalanced across surfaces. The NWS weather data were entered into an algorithm to model NWS WBGT. Results:  Black tennis, black track, red track, and volleyball sand WBGT recordings were greater than NWS estimates (P ≤ .05). When all athletic-surface measurements were combined, NWS (26.85°C ± 2.93°C) underestimated athletic-surface WBGT measurements (27.52°C ± 3.13°C; P < .001). The range of difference scores (−4.42°C to 6.14°C) and the absolute mean difference (1.71°C ± 1.32°C) were large. The difference between the onsite and NWS WBGT measurements resulted in misclassification of the heat-safety activity category 45% (65/143) of the time (= 3.857, P = .05). The WBGT of water was 1.4°C to 2.7°C lower than that of all other athletic surfaces (P = .04). We observed no other differences among athletic surfaces but noted large WBGT measurement variability among athletic playing surfaces. Conclusions:  Clinicians should use an onsite WBGT device to determine environmental conditions and the need for modification of athletic events, especially as environmental conditions worsen. Given the large WBGT variability among athletic surfaces, WBGT measurements should be obtained from each athletic surface.

Measuring wet bulb globe temperatures at point-of-exertion in worldwide UK military settings: a longitudinal observational study determining the accuracy of a portable WBGT monitor

2020 ◽  
pp. bmjmilitary-2020-001551
Author(s):  
Patricia Falconer Hall ◽  
J Blackadder-Coward ◽  
H Pynn
Keyword(s):  
Feasibility Study ◽  
Large Scale ◽  
Armed Forces ◽  
Weather Conditions ◽  
Paired Data ◽  
Wet Bulb Globe Temperature ◽  
User Input ◽  
Globe Temperature ◽  
Set Up ◽  
The Uk

IntroductionHeat illness among the UK Armed Forces is usually exertional, and therefore preventable, yet the incidence has not reduced since 2011. JSP 539 explicitly states that wet bulb globe temperature (WBGT) should be measured ‘at the location of greatest heat risk’, not ‘that of most convenience’. A handheld WBGT tracker used at point-of-exertion could reduce this incidence if proven to be as accurate as the current in-service device.MethodsLongitudinal observational comparison and equipment feasibility study of the Kestrel 5400 and QUESTemp 34 (QT-34) in worldwide firm base and deployed UK Armed Forces locations. The locations chosen were Kenya, South Sudan, Belize, Tidworth, Aldershot and Brecon. Paired data points of WBGT readings were collected from November 2017 to August 2018 in all weather conditions.ResultsWBGT readings were comparable between the QT-34 and Kestrel 5400 across the UK and overseas. In addition, there was no change in accuracy between readings taken from the Kestrel 5400 when tripod-mounted and handheld. The Kestrel was easy to set up and far less susceptible to resupply or power supply limitations, as it requires no user input for wet bulb temperature, and runs on AA batteries.ConclusionThis equipment feasibility study has shown that the Kestrel 5400 gives an acceptable accuracy and is easier to use than the QT-34. The authors recommend that the Kestrel 5400 is introduced as an adjunct to the QT-34, and its use within the military setting monitored through ongoing comparative data collection in a large-scale proof-of-concept study.

scholarly journals Analysis of Hygrothermal Microclimatic (HTM) Parameters in Specific Food Storage Environments in Slovakia

2020 ◽  
Vol 17 (6) ◽  
pp. 2092
Author(s):  
Iveta Marková ◽  
Ivana Tureková ◽  
Jana Jaďuďová ◽  
Emília Hroncová
Keyword(s):  
Heat Exposure ◽  
Food Storage ◽  
Winter Period ◽  
Temperature Changes ◽  
Wet Bulb Globe Temperature ◽  
Cold Room ◽  
Environment Temperature ◽  
The Difference ◽  
Globe Temperature ◽  
The Individual

The quality of work environment, temperature changes and humidity must be controlled in every production process and in the locations where employees are present. The aim of this paper is to objectively assess the exposure of employees to microclimatic factors of the workplace environment: the warehouse, changing rooms, office and cold room refrigerator. Data were obtained in real working conditions. The heat stress due to cold and heat exposure in the individual locations was evaluated using the WBGT (wet bulb globe temperature) indicator. The parameters of the hygrothermal microclimate (HTM) were objectified by a QUES Temp 44/46 T spherical thermometer. The measurements were performed both in cold and hot periods of the year. The measurements confirmed standard temperatures for individual types of interiors in the winter period, but in the summer period there was a variability of results, leading to the thermal discomfort of employees. The assessment of the WBGT index revealed that nearly 80% of employees are susceptible to hypothermia as a result of thermal stress conditions. It was proven that the temperatures measured by a spherical thermometer in the hottest room were 8.62% higher than the calculated operating temperature, while the difference in the cold room refrigerator was only 1.28% higher.

Wet Bulb Globe Temperature Use in National Collegiate Athletic Association Football Bowl Subdivision Athletic Training Staffs

2020 ◽  
Vol 25 (6) ◽  
pp. 314-317
Author(s):  
Garrison A. Chan ◽  
Dale R. Wagner
Keyword(s):  
Athletic Training ◽  
National Collegiate Athletic Association ◽  
Athletic Trainers ◽  
Geographical Location ◽  
Football Bowl Subdivision ◽  
Wet Bulb Globe Temperature ◽  
Association Football ◽  
National Athletic Trainers Association ◽  
Globe Temperature ◽  
The University

Heat illnesses present a risk for athletes, especially football players. The National Athletic Trainers’ Association established recommendations to prevent heat illnesses, which include measuring wet bulb globe temperature (WBGT). This study aimed to determine the prevalence of WBGT use among the 130 National Collegiate Athletic Association Football Bowl Subdivision athletic training staffs. Of 82 respondents, 59 use WBGT to assess heat stress. The majority of Football Bowl Subdivision training programs (72% of respondents) use the WBGT, but adherence to this National Athletic Trainers’ Association recommendation varies throughout the season (practice versus games) and is likely influenced by the geographical location of the university.

scholarly journals Variations in Athlete Heat-Loss Potential Between Hot-Dry and Warm-Humid Environments at Equivalent Wet-Bulb Globe Temperature Thresholds

2020 ◽  
Author(s):  
Jennifer Vanos ◽  
Andrew Grundstein
Keyword(s):  
Heat Loss ◽  
Sports Medicine ◽  
Evaporative Cooling ◽  
Weather Conditions ◽  
Activity Levels ◽  
Maximum Heat ◽  
Wet Bulb Globe Temperature ◽  
Stressful Environment ◽  
Weather Stations ◽  
Globe Temperature

Context: Many organizations associated with sports medicine recommend using wet-bulb globe temperature (WBGT)-based activity-modification guidelines that are uniform across the country. However, there is no consideration about whether the WBGT thresholds are appropriate for different weather conditions, such as warm-humid (WH) relative to hot-dry (HD), given known differences in physiological responses to these environments.Objective: To identify if regions with drier conditions and greater evaporative cooling potential should consider using WBGT activity-modification thresholds that are different from those with more humid weather.Design: Observational study.Setting: Weather stations across the contiguous United States.Main Outcome Measure(s): A 15-year hourly WBGT dataset from 217 weather stations across the contiguous United States was used to identify particular combinations of globe temperature, wet-bulb temperature, and air temperature that produce WBGTs of 27.9°C, 30.1°C, and 32.3°C. A total of 71 302 observations were clustered into HD and WH environmental conditions. From these clusters, maximum heat-loss potential and heat-flux values were modeled at equivalent WBGT thresholds with various activity levels, clothing, and equipment configurations.Results: We identified strong geographic patterns, with HD conditions predominant in the western half and WH conditions predominant in the eastern half of the country. Heat loss was systematically greater in HD than in WH conditions, indicating an overall less stressful environment even at equivalent WBGT values. At a WBGT of 32.3°C, this difference was 11 W∙m−2 at an activity velocity of 0.3 m∙s−1, which doubled for an activity velocity of 0.7 m∙s−1. The HD and WH difference increased with WBGT value, demonstrating that evaporative cooling differences between HD and WH conditions were even greater at a higher, rather than lower, WBGT.Conclusions: The potential heat loss was consistently greater in HD than WH environments despite equal WBGTs. These findings support the need for further clinical studies to determine the appropriate WBGT thresholds based on environment and physiological limits to maximize safety, yet also avoid unnecessary limitations.

scholarly journals Moisture content of cereals at harvesting time by comparing microclimate values and standard weather data

1993 ◽  
Vol 41 (3) ◽  
pp. 167-178
Author(s):  
A.J. Atzema
Keyword(s):  
Moisture Content ◽  
Surface Temperature ◽  
Air Temperature ◽  
Weather Conditions ◽  
Dew Point ◽  
Weather Data ◽  
Daily Cycle ◽  
The Difference ◽  
High Equilibrium ◽  
Screen House

The moisture content of wheat and barley together with the weather elements were measured at 3 different experimental sites in the Netherlands in 1990-91. The difference in the dew point temperature in the screen[house] and in the field was small. However, the differences between air temperature in the screen and those at different heights in wheat and in barley stands were considerable. In daytime the surface temperature of barley was higher than that of wheat under the same weather conditions as a result of a higher absorbtion coefficient. Both for wheat and barley, the maximum difference between the calculated moisture content was 0.5%, using the air temperature at 1.5 m height from the nearest standard weather station and the surface temperature of the spikes. Barley had a greater daily cycle in the moisture content of the grains than wheat as a result of a high equilibrium moisture content during the night and a low one in daytime.

scholarly journals Process-based simulation of seasonality and drought stress in monoterpene emission models

2009 ◽  
Vol 6 (5) ◽  
pp. 8961-9004
Author(s):  
R. Grote ◽  
T. Keenan ◽  
A.-V. Lavoir ◽  
M. Staudt
Keyword(s):  
Drought Stress ◽  
Environmental Conditions ◽  
Seasonal Dynamics ◽  
Weather Conditions ◽  
Weather Data ◽  
Emission Model ◽  
Monoterpene Emission ◽  
Air Chemistry ◽  
Emission Models ◽  
Species Specific

Abstract. Canopy emissions of volatile hydrocarbons such as isoprene and monoterpenes play an important role in air chemistry. They depend on various environmental conditions, are highly species-specific and are expected to be affected by global change. In order to estimate future emissions of these isoprenoids, differently complex models are available. However, seasonal dynamics driven by phenology, enzymatic activity, or drought stress strongly modify annual ecosystem emissions. Although these impacts depend themselves on environmental conditions, they have yet received little attention in mechanistic modelling. In this paper we propose the application of a mechanistic method for considering the seasonal dynamics of emission potential using the ''Seasonal Isoprenoid synthase Model'' (Lehning et al., 2001). We test this approach with three different models (GUENTHER, Guenther et al., 1993; NIINEMETS, Niinemets et al., 2002a; BIM2, Grote et al., 2006) that are developed for simulating light-dependent monoterpene emission. We also suggest specific drought stress representations for each model. Additionally, the proposed model developments are compared with the approach realized in the MEGAN (Guenther et al., 2006) emission model. Models are applied to a Mediterranean Holm oak (Quercus ilex) site with measured weather data. The simulation results demonstrate that the consideration of a dynamic emission potential has a strong effect on annual monoterpene emission estimates. The investigated models, however, show different sensitivities to the procedure for determining this seasonality impact. Considering a drought impact reduced the differences between the applied models and decreased emissions at the investigation site by approximately 33% on average over a 10 year period. Although this overall reduction was similar in all models, the sensitivity to weather conditions in specific years was different. We conclude that the proposed implementations of drought stress and internal seasonality strongly reduce estimated emissions and indicate measurements are needed to further evaluate the models.

scholarly journals Heat Stress Management in the Military: Wet-Bulb Globe Temperature Offsets for Modern Body Armor Systems

2021 ◽  
pp. 001872082110052
Author(s):  
Andrew P. Hunt ◽  
Adam W. Potter ◽  
Denise M. Linnane ◽  
Xiaojiang Xu ◽  
Mark J. Patterson ◽  
...  
Keyword(s):  
Core Temperature ◽  
Environmental Conditions ◽  
Body Armor ◽  
Body Core Temperature ◽  
Wet Bulb Globe Temperature ◽  
Exertional Heat Illness ◽  
Ballistic Protection ◽  
Body Core ◽  
Heavy Work ◽  
Globe Temperature

Objective The aim of this study was to model the effect of body armor coverage on body core temperature elevation and wet-bulb globe temperature (WBGT) offset. Background Heat stress is a critical factor influencing the health and safety of military populations. Work duration limits can be imposed to mitigate the risk of exertional heat illness and are derived based on the environmental conditions (WBGT). Traditionally a 3°C offset to WBGT is recommended when wearing body armor; however, modern body armor systems provide a range of coverage options, which may influence thermal strain imposed on the wearer. Method The biophysical properties of four military clothing ensembles of increasing ballistic protection coverage were measured on a heated sweating manikin in accordance with standard international criteria. Body core temperature elevation during light, moderate, and heavy work was modeled in environmental conditions from 16°C to 34°C WBGT using the heat strain decision aid. Results Increasing ballistic protection resulted in shorter work durations to reach a critical core temperature limit of 38.5°C. Environmental conditions, armor coverage, and work intensity had a significant influence on WBGT offset. Conclusion Contrary to the traditional recommendation, the required WBGT offset was >3°C in temperate conditions (<27°C WBGT), particularly for moderate and heavy work. In contrast, a lower WBGT offset could be applied during light work and moderate work in low levels of coverage. Application Correct WBGT offsets are important for enabling adequate risk management strategies for mitigating risks of exertional heat illness.

scholarly journals The Role of Environmental Conditions on Marathon Running Performance in Men Competing in Boston Marathon from 1897 to 2018

2019 ◽  
Vol 16 (4) ◽  
pp. 614 ◽  
Author(s):  
Pantelis Nikolaidis ◽  
Stefania Di Gangi ◽  
Hamdi Chtourou ◽  
Christoph Rüst ◽  
Thomas Rosemann ◽  
...  
Keyword(s):  
Wind Speed ◽  
Weather Conditions ◽  
Marathon Running ◽  
Marathon Runners ◽  
Wet Bulb Globe Temperature ◽  
Generalized Additive Mixed Models ◽  
Additive Mixed Models ◽  
Boston Marathon ◽  
Globe Temperature

This study investigated the effects of weather conditions on male performance during the Boston Marathon from 1897 to 2018. A total of 383,982 observations from 244,642 different finishers were analysed using Generalized Additive Mixed Models. All runners, annual top 100 finishers and annual top ten finishers were considered. Weather conditions, on race day, were: average air temperature (°C), precipitations (mm), wet-bulb globe temperature (WBGT) (°C), wind speed (km/h), wind direction (N, S, W, E) and pressure (hPa). These effects were examined in multi-variable models with spline smooth terms in function of calendar year. Temperature, when increasing by 1 °C, was related to worsened performance for all groups (i.e., by 00:01:53 h:min:sec for all finishers, p < 0.001). Wind coming from the West, compared to wind coming from other directions, was the most favourable for performance of all groups of finishers. Increasing precipitations worsened performances of top 100 (estimate 00:00:04 h:min:sec, p < 0.001) and top 10 finishers (estimate 00:00:05 h:min:sec, p < 0.001). Wind speed, when increasing by 1 km/h, was related to worsened performance for all finishers (estimate 00:00:19 h:min:sec, p < 0.001), but not for top 100 group, where performances were 00:00:09 h:min:sec faster, p < 0.001. Pressure and WBGT were examined in uni-variable models: overall, performances worsened as pressure and WBGT increased. Our findings contributed to the knowledge about the effect of weather conditions on performance level in male marathon runners.

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