Heat waves in Central Europe and their circulation conditions

Abstract

The research objectives were to describe heat waves (HWs) in Central Europe and define the synoptic situations that cause their occurrence. In this article, a hot day was defined as a day when the maximum temperature was above the 95th annual percentile and an HW was considered a sequence of at least five hot days. In the analysed multi-year period and study area, 11 HWs were observed in the north and 51 HWs were observed in the south. The occurrence of HWs was mainly connected with positive anomalies of sea level pressure and with the 500 hPa level, which shows the presence of high-pressure systems. HWs were also accompanied by positive T850 and precipitable water (PW) anomalies.

Warm spells in Northern Europe in relation to atmospheric circulation

“…On average, the lowest number of WSs was recorded between 1981 and 1990, and the highest in the first decade of the twenty-first century. Similar results were also obtained for Central Europe (Tomczyk and Bednorz 2015). The increase in frequency of extreme weather phenomena, including heat waves, was found in the Czech Republic (Kyselý 2010), Poland (Kossowska-Cezak 2010; Tomczyk 2014b), Serbia (Unkašević and Tošić 2009), Ukraine (Shevchenko et al 2014) and Spitsbergen (Tomczyk and Bednorz 2014b).…”

“…A warm spell (WS) was considered to be a sequence of at least five relatively warm days. The similar method for distinguishing heat waves was applied earlier in the analysis for the occurrence of heat waves in Central Europe (Tomczyk and Bednorz 2015) and for the variable climatic conditions of the Arctic (Tomczyk and Bednorz 2014b).…”

Climate Change Influence on Agriculture and the Water-Energy-Food Nexus in Central and Eastern European Countries

“…They have become common during summertime in Bulgaria and south Romania (Simeonov et al, 2013), with dangerous impacts on agriculture associated with increased heat stress episodes. As recently presented at the EU General Assembly 2016, the summer of 2015 was the warmest ever observed in Central Europe, especially due to overall severity of HW (Lhotka et al, 2016), continuing the trend identified by Tomczyk and Bednorz (2016) of significantly increased numbers of HW between 2001 and 2010 as compared to [1981][1982][1983][1984][1985][1986][1987][1988][1989][1990]. Similarly, according to , the CMR has witnessed decreasing trends in cold-related indices, especially in the number of frost days, and increasing trends in warm-related ones.…”

“…Changes in air temperature in different regions of Europe have shown upward trends, with frequent occurrence of extremely hot months, especially during summertime (Tomczyk and Bednorz, 2016). In Central Europe, the average number of hot days has increased over the past ten years, occurring mostly between April and October and with maxima in June through August (Tomczyk and Bednorz, 2016).…”

“…In Central Europe, the average number of hot days has increased over the past ten years, occurring mostly between April and October and with maxima in June through August (Tomczyk and Bednorz, 2016). Heat waves (HW), characterized by persistence of hot days over a period of time (usually five days or more), may have significant negative social and agricultural effects.…”