Monika Okoniewska
Articles
Heat-stress threats to the human body around noon on very hot days in Poland
Przegląd Geograficzny (2020) tom 92, zeszyt 3, pp. 361–376 | 
Full text
doi: https://doi.org/10.7163/PrzG.2020.3.3
Abstract
This article seeks to analyse the universal thermal climate index (UTCI, °C), in order to characterise hazards associated with high air temperature that may possibly occur in Poland around noon on very hot days. Values for the index (calculated for UTC by reference to air temperature (°C), relative humidity (%), wind speed (v·ms-1) and cloudiness (%)) related to from the Polish cities of Kołobrzeg, Poznań and Kraków, and to the period 2001–2018. Mean values with standard deviations were calculated, with minimum and maximum values noted, amplitudes, lower and upper quartiles and the skewness coefficient. One-way analysis of variance was deployed to determine whether UTCI values at midday on very hot days differ significantly from month to month. The frequency of occurrence of different intensities of heat stress was also determined. In each case, analysis related to both the overall period and individual years.
Hours around noon on very hot days were mainly associated with “moderate” or “severe” heat stress, though instances “very sever heat stress” may also arise. The greatest threat of thermal heat stress could be noted for July and August, with conditions noticeably more severe in Kraków than the other stations studied. Kołobrzeg faced the most-limited hazard associated with the occurrence of heat stress, and only in July may “very severe heat stress” appear there sporadically. In turn, Poznań – located in a region with bioclimatic conditions typical for Poland – was rather characterised by “moderate” or “severe heat stress”.
Equally, on a majority of the very hot days studied, all three stations recoded above-average UTCI values, with this fact making it clear that when a high level of thermal stress arises it may be rather a country-wide phenomenon. The most stable, near-average conditions characterised May, while biothermal differentiation peaked in July and August. Analysis of variance showed that, other than in relation to April in Poznań, levels of thermal stress on hot days did not differ significantly from one month to another.
Analyses of the variability to values for the multi-year universal thermal climate index revealed an increase over time for maxima, especially in Kraków. This may point to an intensified risk associated with overheating of the body, in the south of Poland in particular. In addition, calculations confirm both spatial and temporal differentiation of biothermal conditions. Years in which hot days proved particularly burdensome were 2005, 2007, 2010 and 2013.
Keywords: heat stress, very hot days, noon hours, universal thermal climate index, UTCI
[monika.okoniewska@ukw.edu.pl], Uniwersytet Kazimierza Wielkiego w Bydgoszczy, Instytut Geografii
Citation
APA: Okoniewska, M. (2020). Zagrożenie organizmu człowieka stresem cieplnym występujące w godzinach okołopołudniowych w czasie dni upalnych. Przegląd Geograficzny, 92(3), 361–376. https://doi.org/10.7163/PrzG.2020.3.3
MLA: Okoniewska, Monika. "Zagrożenie organizmu człowieka stresem cieplnym występujące w godzinach okołopołudniowych w czasie dni upalnych". Przegląd Geograficzny, vol. 92, no. 3, 2020, pp. 361–376. https://doi.org/10.7163/PrzG.2020.3.3
Chicago: Okoniewska, Monika. "Zagrożenie organizmu człowieka stresem cieplnym występujące w godzinach okołopołudniowych w czasie dni upalnych". Przegląd Geograficzny 92, no. 3 (2020): 361–376. https://doi.org/10.7163/PrzG.2020.3.3
Harvard: Okoniewska, M. 2020. "Zagrożenie organizmu człowieka stresem cieplnym występujące w godzinach okołopołudniowych w czasie dni upalnych". Przegląd Geograficzny, vol. 92, no. 3, pp. 361–376. https://doi.org/10.7163/PrzG.2020.3.3
Przegląd Geograficzny (2018) tom 90, zeszyt 1, pp. 53-75 | Full text
doi: https://doi.org/10.7163/PrzG.2018.1.3
Abstract The purpose of the work detailed here was to reveal the diurnal variability characterising values for air temperature and vapour pressure in Poland. To this end, reference was made to meteorological data – concerning air temperature (°C) and water vapour pressure (hPa) – derived from eight observation terms over the period 1991-2000, and from the Polish cities of Koszalin, Białystok, Poznań, Warsaw, Wrocław and Rzeszów. These data were used to calculate average diurnal values for each of these meteorological elements, with graphs constructed to show the averaged daily courses for air temperature and water vapour pressure, as well as the course of averaged diurnal extreme values and amplitudes in regard to both elements, together with the hours associated with them. All analyses were carried out for consecutive ten-day periods of the year. Because of the uneven changes in the variables throughout the daytime, extreme values for air temperature and water vapour pressure were approximated using an asymmetric function. The diurnal courses to thermal and humidity conditions in the Polish cities under study are found to be characterised by a certain variability, both temporally and spatially. In particular, there are significantly fewer instances of stable weather conditions during the summer season, than in winter. The hours of occurrence of air temperature minima depend on the season. In winter they occur much later, about 5-6 a.m., while in the warm half of the year they are noted at approximately 2 a.m. Diurnal maxima for air temperature appear around the same time of day, usually at about 1 p.m. year-round. Analysis of the spatial structure characterising variability in diurnal air temperature showed SE Poland (Rzeszów) to be the warmest region in summer during daytime hours. Summer nights are hottest in the south-west (Wrocław) and middle part of Poland (Warsaw). In winter, the privileged stations in respect of thermal conditions are Wrocław and Koszalin, during daytime hours and at night respectively. The diurnal course sees water vapour pressure rise during the hours of daytime, and decrease at night. In turn, annual variability is characterised by significant summer increases and winter decreases. In the summer, the diurnal courses for water vapour pressure are characterised by the presence of two minima and two maxima per day. The first diurnal minimum is usually recorded in the morning, between 2 a.m. and 6 a.m., albeit slightly later in winter, while the second, appearing in the warm season, is observed between 12 a.m. and 4 p.m. In the case of the diurnal maximum, the first, is more seasonally dependent than the minimum, in that it occurs between noon and 4 p.m. in winter, most often around 8 a.m. A second one is noted between 4 and 8 p.m. The spatial range of occurrence of different values for water vapour pressure points to a rise in the western part of the country in the cool half of the year, while south-eastern Poland is more privileged in this regard in the summer.
Keywords: przebieg dobowy, temperatura powietrza, ciśnienie pary wodnej, Polska
[monika.okoniewska@ukw.edu.pl], Uniwersytet Kazimierza Wielkiego w Bydgoszczy, Instytut Geografii
Citation
APA: Okoniewska, M. (2018). Dobowy przebieg temperatury i wilgotności powietrza w Polsce w kolejnych dekadach roku. Przegląd Geograficzny, 90(1), 53-75. https://doi.org/10.7163/PrzG.2018.1.3
MLA: Okoniewska, Monika. "Dobowy przebieg temperatury i wilgotności powietrza w Polsce w kolejnych dekadach roku". Przegląd Geograficzny, vol. 90, no. 1, 2018, pp. 53-75. https://doi.org/10.7163/PrzG.2018.1.3
Chicago: Okoniewska, Monika. "Dobowy przebieg temperatury i wilgotności powietrza w Polsce w kolejnych dekadach roku". Przegląd Geograficzny 90, no. 1 (2018): 53-75. https://doi.org/10.7163/PrzG.2018.1.3
Harvard: Okoniewska, M. 2018. "Dobowy przebieg temperatury i wilgotności powietrza w Polsce w kolejnych dekadach roku". Przegląd Geograficzny, vol. 90, no. 1, pp. 53-75. https://doi.org/10.7163/PrzG.2018.1.3