Thermal Conditions in the City of Poznań (Poland) during Selected Heat Waves

Abstract

Abstract:The aim of the study was to characterise the occurrence of hot days and heat waves in Poznań in the 1966-2015 period, as well as to describe the thermal conditions in the city during selected heat waves between 2008 and 2015. The basis of the study was the daily maximum and minimum air temperature values for Poznań-Ławica station from 1966-2015 and the daily values of air temperature from eight measuring points located in the city in various land types from 2008 to 2015. A hot day was defined as a day with T max above the 95th annual percentile (from 1966 to 2015), while a heat wave was assumed to be at least five consecutive hot days. The research study conducted shows the increase of T max , number of hot days and frequency of heat waves in Poznań over the last 50 years. Across the area of the city (differentiation of urban area types according to Urban Atlas 2012), there was a great diversity of thermal conditions during the heat waves analysed.

Cold Waves in Poznań (Poland) and Thermal Conditions in the City during Selected Cold Waves

“…In particular measurement points, for the analyzed cold days, the differences varied from 1.1 to 5.0 • C. A similar range of differences was also observed during selected hot days, with a maximum of 5.2 • C [20]. The coldest areas include semi-natural urban green areas, sports and recreation areas, as well as forests and fallow arable land.…”

“…A detailed description of the performed calculations and used methods and tools was presented in a paper concerning thermal conditions in the city during selected heat waves [20].…”

“…The study of the temperature field in urban areas at a resolution of 30 × 30 m allows distinguishing part of the city exposed to very high [20] and low values of air temperature. These thermal conditions are the cause of thermal stress both in the summer and winter seasons.…”

“…In this study, the obtained maps allow to compare the different types of land cover according to Urban Atlas in terms of their thermal conditions. This paper constitutes a continuation of research on thermal conditions in the city during extreme air temperatures [20]. In the context of forecasts of the UN [21] showing an increase in the number of population living in cities, it is desirable to thoroughly investigate thermal conditions in the city both in the case of high and low temperatures.…”

Understanding the Impacts of Climate Change on Health to Better Manage Adaptation Action

“…There are further research papers addressing the effects of temperatures on health in this issue, including analyses on heatwaves and cold spells, and reduced productivity in relation to heat. Two of the papers in this special issue focus on the incidence of heatwaves [17] and cold spells [18] over a 50 year period in the city of Poznan, Poland. The authors highlight how the diversity of land type is reflected by diverse thermal conditions across the city compared with the reference monitoring stations, and the increased frequency of heatwave and reduced frequency of cold spells over the period studied.…”