Extreme ultra-short-term changes in air temperature in January in southern Poland (the example of Sosnowiec) against the background of atmospheric circulation conditions

Large short-term changes in air temperature affect the functioning of living organisms in the environment and human activities. For this reason, a study of extreme positive and negative 10 min temperature changes and their causes related to atmospheric circulation was undertaken. Air temperature data for January in the period 2001–2017 in southern Poland (Sosnowiec) were analysed. Extreme ultra-short-term temperature changes were considered to be values less than or equal to 0.1 percentile (extreme temperature drops) and greater than or equal to 99.9 percentile (extreme temperature increases). The extreme ultra-short-term negative air temperature change was − 7.2°C/10 min, while the positive change was + 3.5 °C/10 min. Extreme ultra-short-term negative air temperature changes in southern Poland in January occur most frequently with the advection of air from the west (43% of cases), the inflow of maritime Polar old (transformed) air over Poland (25% of cases), western cyclonic (Wc) and north-western cyclonic (NWc) situations, a total of 34% of cases), the passage of the atmospheric front over southern Poland (59% of cases), especially a cold front (68% of cases with a front). Extreme ultra-short-term positive changes of air temperature in southern Poland in January occur most frequently with the advection of air from the south-west (43% of cases), the inflow of continental Polar air (42% of cases), anticyclonic situations (72% of cases), the occurrence of a high-pressure wedge over southern Poland (26% of cases), situations without atmospheric front (80% of cases). The direction of advection plays a secondary role in determining the values of extreme short-term changes in air temperature. More important is the speed of the influx of this air mass. Extreme ultra-short-term temperature changes are partly explained by circulation conditions. Rapid temperature changes can also occur as a result of small-scale processes in the atmosphere.