Akademik Veri Yönetim Sistemi
Pure and Applied Geophysics, cilt.180, sa.7, ss.2889-2900, 2023 (SCI-Expanded, Scopus)
The upstream atmospheric blocking and the North Atlantic Oscillation (NAO) has been recognized as one of the key sources for extreme temperatures and climate variability in the Euro-Mediterranean region. In this study, their interplay with the pronounced temperature anomalies is examined from the perspective of upstream blocking and the positive NAO. To delineate this association, a two-dimensional blocking index and a cold wave detection method were used for their objective identification. The cold wave method uses spatiotemporally varying temperature threshold to identify cold snaps. The role of upper levels was elucidated by the analysis of time-mean and climatological anomalies of the 500 hPa geopotential height. It was noted that cold snaps were located on the downstream of the blocking ridge over the eastern Atlantic. For the study period (10–25 January 2022), warmer than average climate (1980–2009) conditions, with positive temperature anomalies which ranged from 1 °C to 5 °C, were experienced in western Europe while colder than average conditions, with negative temperature anomalies from − 6 °C to − 1 °C, took place in central and eastern Europe. The instantaneous blocking frequency was approximately 50–60% and the episode of large-scale blocking frequency was 60–75% over western Europe. The positive NAO phase persisted for two weeks. Cold waves lasted approximately 3–12 days in northern parts of Spain and 3–10 days in western of Türkiye. Analysis of this upstream blocking driven cold snaps provides insight into the origin of extreme temperatures and climate variability in the Euro-Mediterranean region.