Heat Warnings in Switzerland: Reassessing the Choice of the Current Heat Stress Index

Abstract

High temperatures lead to heat-related human stress and an increased mortality risk. To quantify heat discomfort and the relevant dangers, heat stress indices combine different meteorological variables such as temperature, relative humidity, radiation and wind speed. In this paper, a set of widely-used heat stress indices is analyzed and compared to the heat index currently used to issue official heat warnings in Switzerland, considering 28 Swiss weather stations for the years 1981–2017. We investigate how well warnings based on the heat index match warning days and warning periods that are calculated from alternative heat stress indices. The latter might allow for more flexibility in terms of specific warning demands and impact-based warnings. It is shown that the percentage of alternative warnings that match the official warnings varies among indices. Considering the heat index as reference, the simplified wet bulb globe temperature performs well and has some further advantages such as no lower bound and allowing for the calculation of climatological values. Yet, other indices (e.g., with higher dependencies on humidity) can have some added value, too. Thus, regardless of the performance in terms of matches, the optimal index to use strongly depends on the purpose of the warning.

Empirical Model of Thermal Comfort for Medium-Sized Cities in Subtropical Climate

“…Thus, the variance inflation factor (VIF) was calculated for the previously selected variables. As stated by Marquardt (1970) [81], variables characterized by VIF values greater than 10 should be excluded; however, values above the threshold established [54] are not verified (Table 3), so it was decided to maintain the relative humidity in the construction of the model. The relative air humidity presented a positive, but weak, correlation with the BMI, as well as with the MRT, with R equal to 0.0588.…”

“…Thus, most studies aim at calibrating the interpretative ranges of different comfort indexes to solve issues raised for countless different locations [14,20,26,27,[53][54][55][56][57]. However, the calibration of the thermal comfort ranges of a given index not always answers all the questions raised about the thermal comfort of a given location [14,54].…”

“…Thus, most studies aim at calibrating the interpretative ranges of different comfort indexes to solve issues raised for countless different locations [14,20,26,27,[53][54][55][56][57]. However, the calibration of the thermal comfort ranges of a given index not always answers all the questions raised about the thermal comfort of a given location [14,54]. Therefore, the development of a predictive model based on the physiological and subjective aspects of the population, as well as on the physical aspects of the reference environment, becomes a solution for better interpretations of the bioclimatic aspects for medium-sized cities [25,29,54,[58][59][60].…”

Heat Wave Variations Across China Tied to Global SST Modes

“…Thus, studies focused on the humanistic society usually used heat index or similar heat wave indices such as wet bulb temperature, wet bulb globe temperature in the sun, wet bulb globe temperature, apparent temperature, effective temperature, and discomfort index, measuring the combined effects of temperature, humidity, radiation, and winds, which have significant influences on the heat discomfort and relevant dangers of increased morbidity and mortality risk (Anderson et al, ; Chong & Zhu, ; Santee & Wallace, ). For example, available literature has suggested that the wet bulb globe temperature and heat index should be applied as alerts in the heat warning system (Burgstall et al, 2019; Morris et al, ). At present, more and more studies focus on the applicability of heat index in the heat warnings including the flexibility of specific warning demands, the impact‐based warnings, and workplace heat hazard assessment, since the human adaption of heat stress is more complex with specifically local conditions.…”

Low cost design for measuring and assessing climatic indices for safe working environment

“…Workers are frequently exposed to different environmental stresses, which may decrease occupational efficiency and may threaten lives. For decades companies and organizations are trying to develop their own systems and utilities and trying to setup and design their working environment in ways to increase the levels of comfort and productivity, and minimize potential of risks and hazards [1][2][3]. Physical exertion in a humid and hot working environment may lead to safety and productivity issues physical strain and occupational heat hazards such as rash, cramps and syncope [4].…”