The occurrence of heat waves in Europe and their circulation conditions

The objective of the paper was to characterize the occurrence of heat waves in Europe between 1976 and 2015 and to determine circulation conditions causing their occurrence. The heat waves were recognized as a sequence of at least 5 consecutive hot days. The hot day was defined as a day on which daily maximum air temperature was higher than 95th percentile of all the values in the analyzed period. The conducted research showed an increase in the number of heat waves and their duration in the analyzed period. The longest heat wave occurred in 2010, in Moscow, which lasted 45 days. The most intense changes were observed in the eastern and south-eastern regions. The occurrence of heat waves was mainly connected with positive anomalies of atmospheric pressure at sea level, geopotential height of 500 hPa, and temperature on isobaric surface 850 hPa.