The Period 2015-2022 – Eight Warmest Years over Europe and Türkiye: Linkage Between Atmospheric Dynamics and Heatwaves

Abstract

Abstract The period 2015–2022 was reported to be the warmest on record globally. This study focused on the summer seasons (June, July, August - JJA) of this hot period over the study region of Europe and Türkiye for investigating the linkage between atmospheric dynamics and heatwaves. The JJA mean temperature anomalies with respect to the reference climate (1981–2010) over the study region showed that 2022, 2021 and 2018 were the warmest top three years. The linkage between atmospheric blocking events and summer heatwave events were elaborated by implementing a percentile-based heatwave identification method and a two dimensional atmospheric blocking identification method. The dynamical role played by the 500-hPa geopotential height (GH500) summer anomalies were also considered, and associated GH500 anomalies computed with respected to the reference climate. It was noted that the hot summer seasons of 2015, 2016, 2018, 2019, 2021 and 2022 were associated with large-scale episode of blocking events, in particular, over the mid-to-high latitudes. Over the southern latitudes, in summer seasons of 2015, 2017 and 2020, heatwave activities were considered to be associated with the large GH500 anomalies, which were attributed to the northerly expansion of sub-tropical atmospheric flow. The horizontal transport of anomalously warm and dry air and together with exacerbated effects of subsidence under large GH500 anomalies were considered to be major contributors that triggered and maintained anomalously high temperatures.