Climatological and synoptic evaluation of heatwave observed over Turkey in May 2020

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This paper examines the climatological and synoptic characteristics of the heatwave that affected Turkey in May 2020. For this purpose, the surface daily maximum temperatures (Tmax) and the heatwaves temporal change recorded in May in the 104-meteorological and climatological stations in Turkey and the heatwave and the upper atmospheric synoptic climatological/meteorological conditions for May 2020 are examined. Results show that May s highest temperature has shown an increasing trend from 1950 to 2000 and more evidently since the 1980s, especially in Eastern- and Southeastern Anatolia. The highest maximum air temperatures in May over the last 71 years were recorded in 2020, 2019, and 1990. Trend analysis shows that an increasing trend at 95 stations characterizes the number of heatwaves and this trend is statistically significant at 22 stations over Turkey from 1950 to 2018. The highest numbers of heatwaves experienced in May during the 1950 -2018 period belong to 2019, 1994, and 2020. The frequency of heatwaves observed in May has also shown an increasing trend since the early 1990s, and this trend is statistically significant at 27 stations. The average duration of the heatwave days in May was 3 days before 1990; this figure also increased significantly to an average of 5.4 days after 2015. In the entire 71-year period, 2020 May was marked by record-breaking maximum temperatures in 32 stations over Turkey. From 15 to 21 May, daily maximum temperature values exceeded 40 °C at 11 stations. The study utilizes ground and upper-level synoptic charts, radiosonde observations, and prognostic maps in the synoptic analysis of the ground level and upper atmosphere. Continental tropical air mass (cT), which moved from over-North Africa under the effect of Azores high-pressure center, has expanded along the Eastern Mediterranean basin since 15 May 2020. The high-level, high-pressure centers and the stable conditions of the “ridge” region (atmospheric blockage) shown in 500 hPa charts have become more effective in most parts of Turkey and caused the breaking of maximum temperature records, especially in the Aegean and Mediterranean regions. When we consider the observed changes in daily maximum temperatures and the characteristics of the heatwaves accelerated during the last decades, we see an increasing likelihood of more frequent and longer heatwaves in Turkey in future decades.

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Heatwaves , maximum air temperatures in May , Record air temperatures in May , Standard atmospheric pressure level , Temp Diagrams

Aegean Geographical Journal

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Aegean Geographical Journal