Characteristics of wind speeds and outdoor thermal sensation considering the effect of wind speeds: An analysis based on hourly data from 1995 to 2021 in Poland

Abstract

AbstractIn this study, characteristics of 10 m height wind speeds (Wsp10) and outdoor human thermal sensation taking wind speeds into account were studied over the period 1995–2021 considering 43 stations in Poland. For estimating hourly Wsp10 from wind speeds measured at different heights, first, the power law exponent was calculated using hourly 10 and 100 m wind speeds obtained from the ERA5 reanalysis project. The power law exponent was much smaller over the Baltic Sea compared to that over Poland. The power law exponent was often larger than 1/7 in Poland, and it varied spatiotemporally. During the period 1995–2021, at 19 of the 43 stations statistically significant monotonic linear trends were observed in Wsp10. It is speculated that land use changes may be one of the causes of these trends in Wsp10, although the land use–Wsp10 relationship was not straightforward. In all seasons, at all stations, except at Kasprowy Wierch (the most elevated station) daytime Wsp10 was higher than the night‐time wind speed. In winter and autumn, the highest Wsp10 occurred around 1300 UTC. In spring and summer, the highest Wsp10 occurred after 1300 UTC. This was probably because in spring and summer the peak temperature occurs later. In all seasons, low/high Wsp10 values were more/less frequent. According to the Beaufort scale and the Parczewski scale, it was understood that both low and high extreme wind conditions have reduced over the period 1995–2021. The Effective Temperature scale indicated increasing/decreasing monotonic linear trends in relatively warm/cold thermal sensation categories. The Wind Chill Temperature exposure risk scale indicated decreasing monotonic linear trends in wind chill. The rising temperature and declining frequency of strong winds are seen as the main causes of these trends.