A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances, and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat by examining the benefits of heat acclimation, cooling strategies, and hyperhydration. Finally, contemporary controversies are summarized and future research directions are provided.

https://journals.physiology.org/doi/pdf/10.1152/physrev.00038.2020

Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies

Extreme updrafts (≥10 m s−1) and wind gusts (≥90 m s−1) are ubiquitous within the low-level eyewall of intense tropical cyclones (TCs). Previous studies suggest that both of these features ...

/pdf/using-simulated-dropsondes-to-understand-extreme-updrafts-3hepwatoj3.pdf

Using Simulated Dropsondes to Understand Extreme Updrafts and Wind Speeds in Tropical Cyclones

. A dataset containing quality-controlled wind observations from 222 tall towers has been created. Wind speed and wind direction measurements covering the 1984–2017 period have been collected from existing tall towers around the world in an effort to boost the utilization of these non-standard atmospheric datasets, especially within the wind energy and research fields. Observations taken at several heights greater than 10 m above ground level have been retrieved from various sparse datasets and compiled in a unique collection with a common format, access, documentation and quality control. For the last, a total of 18 quality control checks have been considered to ensure the high quality of the wind records. Non-quality-controlled temperature, relative humidity and barometric pressure data from the towers have also been obtained and included in the dataset. The Tall Tower Dataset ( Ramon and Lledo ,  2019 a ) is published in the repository EUDAT and made available at https://doi.org/10.23728/b2share.136ecdeee31a45a7906a773095656ddb .

/pdf/the-tall-tower-dataset-a-unique-initiative-to-boost-wind-3zt1g4we9n.pdf

The Tall Tower Dataset: a unique initiative to boost wind energy research

In coastal areas, Tropical Cyclones (TCs) are one of the greatest threats to humanity. Unfortunately, current risk reduction measures are not completely successful in lessening TC's consequences due to the remaining uncertainties in the estimates of key parameters, on which the designs of these measures rely. Because reliable observations of TCs, having affected many regions, are restricted to quite a small number, it is not feasible to derive accurate TC statistics solely based on historical records, without producing large errors. This research presents a comprehensive methodology to effectively overcome the observed data scarcity problem. TCs are stochastically simulated over a period of thousands of years by a numerical model, which results in a long-term database of synthetic TCs, with specifications of the central track and intensity as well as the wind field at each time step. Because TC evolution is heavily dependent on local conditions, the simulation is carried out at a regional scale to maintain relative homogeneity within both the input and outcome, and to reduce computational demand. Since the model has a generalized theoretical framework and contains the worldwide historical weather data, it can be applied to any case study. Once users define the Area Of Interest (AOI), a stepwise calibration procedure is automatically performed by a computer program to achieve the most suitable approach and to specifically determine every single detail of the model for this user-defined AOI. The method is validated though comparisons of observed and simulated TC statistics in the AOI. For a case study of Vietnam in the Western North Pacific, this evaluation proves the model's ability to reproduce the actual TC characteristics and to generate a useable long-term database with an acceptable accuracy for practical projects. Finally, the wind speed maps and the annual exceedance probability maps are provided as possible applications of the model results.

/pdf/long-term-regional-simulation-of-tropical-cyclones-using-a-8rp6jx4i84.pdf

Long-term regional simulation of tropical cyclones using a Generalized Stochastic Empirical Storm Model: A case study in the Western North Pacific

A World Meteorological Organization (WMO) committee evaluated the record sea-level pressure (SLP) measurement of 1089.4 hPa on 30 December 2004 in Tosontsengel, Mongolia (1724.6 m). Although instrumentation and data collection procedures were properly followed according to the assessment of the committee, concern was raised regarding the reliability of SLP adjustment from such a high-elevation station. This paper addresses this concern with a number of analyses that look at relationships between SLP extremes and corresponding station elevation and temperature. First, we selected data from stations extracted from the Integrated Surface Database (ISD-Lite) of NOAA's National Climate Data Center. A spatial analysis indicates that elevation shows little to no association (R2 values essentially zero) to extreme SLP. However, a second analysis between extreme SLP and air temperature indicates that high regionalism exists in spatial correlations (local R2) between those two variables. This relationship to temperature is likely the result of differences in SLP adjustment formulae used around the world. Based on this analysis, on the need to differentiate the SLP values adjusted using extremely cold temperatures (and generally high elevation), and following past WMO SLP guidelines, the WMO Rapporteurs for Climate and Weather Extremes therefore have created two distinct SLP records: (a) highest adjusted SLP (below 750 m), currently 1083.3 hPa recorded on 31 December 1968 at Agata, Evenhiyskiy, Russia; and (b) highest adjusted SLP (above 750 m), currently 1089.4 hPa (by Russian method; 1089.1 hPa by WMO formula) on 30 December 2004 in Tosontsengel, Mongolia. Future WMO guidance regarding SLP adjustment may lead to re-evaluation of this and other SLP records.

The Tosontsengel Mongolia world record sea-level pressure extreme: spatial analysis of elevation bias in adjustment-to-sea-level pressures

This paper details the event, recording instrumentation, and verification of a new world extreme three-second average wind gust record of 113.3 m s–1, measured
on Barrow Island, Australia, during the passage of tropical cyclone Olivia in April 1996, and the public and media reaction to that verification. This record supersedes
the previous extreme of 103.3 m s–1 measured at the Mount Washington Observatory in New Hampshire, USA, in April 1934. Members of a World Meteorological
Organization evaluation committee critically reviewed the data of the Olivia event, determined the Barrow Island wind measurement was valid and established the record. With the announcement of the record, interesting public reaction has occurred and is discussed, as well as the concept of more detailed classification of wind extremes. Although Olivia now holds the record for having the highest wind gust ever measured, this record doesn’t imply that Olivia is the
most intense cyclone recorded. However, planners should be aware that extreme gusts well above the ‘typical’ gusts quoted on the intensity scale are possible for
tropical cyclones, particularly for category 4 and 5 tropical cyclones.

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Documentation and verification of the world extreme wind gust record: 113.3 m s–1 on Barrow Island, Australia, duringpassage of tropical cyclone Olivia

K. Rancourt

Papers

Documentation and verification of the world extreme wind gust record: 113.3 m s–1 on Barrow Island, Australia, duringpassage of tropical cyclone Olivia