Strong heat and cold waves in Poland in relation with the large-scale atmospheric circulation

Abstract

Occurrence of heat and cold waves in Poland in the years 1966-2015 (1966/1967-2015/2016) was described, and their circulation conditions were determined in this study. A heat wave is defined as a period of at least 3 days with Tmax > 30.0°C and a cold wave as a period of at least 3 days with Tmax <− 10.0°C. Heat waves occurred most often in central and southern Poland and cold waves in northeastern Poland. The occurrence of both heat and cold waves is related to high pressure systems. Anticyclonic blocking patterns both in winter and summer inhibit the zonal flow of air masses and intensify the meridional flow. Positive sea level pressure anomalies occurred over the study area, in the case of heat waves up to 3 hPa and in the case of cold waves up to 11 hPa. Perpendicular profiles showing geopotential height and air temperature anomalies in the troposphere were identified for the selected cases of extreme temperature episodes. Centres of geopotential height positive/negative anomalies were detected at the level of 300-250 hPa geopotential height, right over the area of the positive/negative surface temperature extremes.

Occurrence of strong and very strong heat stress in Poland and its circulation conditions

“…Moreover, on the analysed days, much greater anomalies of SLP and z300 hPa were recorded than on average on days with strong heat stress. Considerably stronger baric systems were also revealed by analyses of examples of strong heat waves (Tomczyk and Sulikowska 2018;Tomczyk et al 2019). The study results confirm the change in biometeorological conditions in Poland, manifested in increasingly frequent occurrence of extreme conditions.…”

“…The occurrence of days with the most intensive heat stress was found to be related to the inflow of considerably warmer air masses than on average, as suggested by high positive anomalies of T850 (maximum > 11°C). Earlier, it was evidenced that the occurrence of the warmest days during the selected heat waves was related to the advection of warm air masses, the range of which reached the isobaric level of 250 hPa (Tomczyk et al 2019). A similar range of positive anomalies of air temperature was determined in other numerous studies both from Europe (Tomczyk et al 2017;Tomczyk 2018;Owczarek 2018) and China (Chen et al 2017).…”

“…In summer, these types of systems favour the occurrence of extreme thermal conditions in the form of heat waves, and in winter, cold waves (Ustrnul et al 2010;Porębska and Zdunek 2013;Unkašević and Tošić 2015). Therefore, the effect of atmospheric circulation on thermal conditions, and particularly on the occurrence of thermal extremes in Poland, has been a subject of great interest for many years (Wibig et al 2009;Tomczyk and Bednorz 2016;Wibig 2018;Tomczyk et al 2019).…”

Relationship between Water Temperature of Polish Rivers and Large-Scale Atmospheric Circulation

“…In the majority of regions around the world, contemporary warming is accompanied by an increase in the frequency and intensity of occurrence of heat waves and a decrease in the frequency and intensity of occurrence of cold waves [41,46,47]. Similar trends are also being observed in Europe [48][49][50][51] and Poland [52][53][54][55], whereas the most intense warming is noted in winter and spring, while slight cooling may be observed in autumn. In the opinion of Kenyon and Hegerl [45], all the main indices of atmospheric circulation are characterized by a considerable and universal impact on the probability of occurrence of temperature extremes in Europe.…”

Occurrence and synoptic background of strong and very strong frost in spring and autumn in Central Europe

“…The authors evidenced that disturbances in the upper troposphere co-occurred with strong air temperature anomalies at a level of 850 hPa. The occurrence of the greatest anomalies of heights of isobaric levels in the upper troposphere was also evidenced during other extreme weather phenomena, such as heat waves (Qian et al 2016;Chen et al 2017;Tomczyk et al 2017;Tomczyk et al 2018b;Geirinhas et al 2019), cold waves (Qian et al 2016;Tomczyk et al 2018b;Tomczyk et al 2019) and hot nights (Tomczyk 2018). Many studies evidenced (Qian et al 2016;Chen et al 2017) that the occurrence of extreme weather conditions is preceded by the development of disturbances in the upper troposphere, which can be helpful in forecasting such phenomena.…”