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This article studies the intra-annual and long-term variability in the maximum daily precipitation totals and their association with atmospheric circulation in Kraków. It investigates daily precipitation maxima by year and by month. The research is based on daily precipitation totals in the years 1863–2021 and draws on the calendar of atmospheric circulation types by Niedźwiedź. It examines the frequency of precipitation maxima in individual months and their variation from one year to another. No statistically significant trend of change in precipitation over the study period has been found. All annual maximum daily precipitation totals in Kraków fall into the category of heavy precipitation (>10 mm), and almost 99% qualify as very heavy (>20 mm). In the summer months, these are about 3–4 times higher than in winter. The share of the daily precipitation maximum in the monthly total exceeds 30% in all months. The maximum daily precipitation occurring on 5 August 2021 was the highest in the period that extends from the start of instrumental measurements. The study period saw 12 cases of maximum precipitation that belong to 'flood-inducing' categories (over 70 mm/day). Such cases of the very heaviest precipitation occurred in cyclonic situations: Cc, Bc, Nc, NEc, Ec and SEc. Most spring and summer maxima were seen on days with a cyclonic circulation. The instances of high daily precipitation in the Kraków area led to the flooding of residential and historic buildings, as well as of municipal infrastructure. [ABSTRACT FROM AUTHOR]

W pracy scharakteryzowano obciążenia cieplne człowieka w trzech najgorętszych miesiącach, które wystąpiły w Krakowie na początku XXI w., a mianowicie w lipcu 2006 r., sierpniu 2015 r. i czerwcu 2019 r. Podstawę badań stanowiły wartości wskaźnika UTCI obliczone na bazie czterech elementów meteorologicznych z trzech terminów obserwacji w ciągu doby (6, 12 i 18 UTC). Jako okres referencyjny przyjęto ostatnie trzydziestolecie 1991-2020. W opracowaniu wykorzystano także kalendarz typów cyrkulacji i mas powietrznych nad południową Polską (Niedźwiedź, 1981, 2023). Na postawie średnich wartości charakterystyk termicznych, jak i wskaźnika UTCI, wykazano, że warunki odczuwalne w 3 niezwykle ciepłych miesiącach były podobne. Ogólnie dni ze stresem ciepła (o 12 UTC) było rekordowo dużo: od 70% w sierpniu 2015 r. do 84% w czerwcu 2019 r. Przebieg obciążeń z dnia na dzień był nieco odmienny. Potwierdziło się, zgodnie z dotychczasową wiedzą, że o nasileniu gorąca zadecydowały zarówno charakter cyrkulacji, jak i kierunek adwekcji i typ masy powietrznej. Podczas niezwykle ciepłych miesięcy w dniach z najsilniejszym stresem ciepła przeważała cyrkulacja antycyklonalna z sektora południowego (Sa i SWa), sprowadzająca gorące masy powietrza zwrotnikowego. [ABSTRACT FROM AUTHOR]

The set of meteorological data from the Jagiellonian University station in Kraków is one of the longest‐recorded in central Europe. Measurement records date back to 1826. Based on the average monthly values of air temperature, total cloudiness, water vapour pressure and wind speed at 1200 UTC, the UTCI values were calculated and the occurrence of cold stress (UTCI < −13°C) and heat stress (UTCI > 32°C) was estimated. The variability of the applied measures of thermal stress conditions was studied both annually and in individual seasons (MAM, JJA, SON, DJF). Statistically significant changes in the studied characteristics of the bioclimate were found. Average annual UTCI values increased at the rate of 0.27°C/10 years. In individual seasons, the trend of UTCI changes ranged from 0.10°C/10 years in summer to 0.43°C/10 years in winter. The number of days with cold stress decreased by 1.8 days/10 years and the number of days with heat stress significantly increased (0.5 days/10 years). Two subperiods with different trends of changes were determined. The first covers the years 1826–1940, and the second, 1941–2021. The former indicates a negative UTCI trend of −0.17°C/10 years, and the latter, an increasing trend of 1.09°C/10 years. The last eight decades have brought a decrease in cold days of 6.5/10 years and an increase in heat days of 2.6/10 years. [ABSTRACT FROM AUTHOR]

This paper investigates the relationship between maximum precipitation in Krakow and types of atmospheric circulation in southern Poland, as classified by Niedźwiedź. Three characteristics were used to define this relationship: maximum precipitation (Pmax), its duration (d) and probability of exceedance (p). The input data came from Kraków's uniquely long and homogenous pluviographic record spanning the period 1886-2007. Hourly precipitation values for the maximum precipitation events were identified and arranged in 1-24 hour intervals. They were then processed using the generalized extreme value (GEV) distribution to produce quantiles of maximum precipitation totals in each of the intervals and broken down by the corresponding circulation type. Differences between the development mechanisms are manifested in relationships between precipitation characteristics and their measure of randomness, i.e. exceedance probability. This paper demonstrates that maximum precipitation events depend on their duration d and atmospheric circulation. The maximum short-duration (one-hour) events occur primarily in either of two circulation types: (i) cyclonic with advection from the east and from the southeast or (ii) low-pressure centre and cyclonic trough. Maximum long-duration precipitation events (24 hour), on the other hand, occur in the cyclonic type of circulation with advection from the north and from the northeast. [ABSTRACT FROM AUTHOR]