Connecting North Atlantic SST Variability to European Heat Events over the Past Decades.

Krüger, Julian , Kjellsson, Joakim , Kedzierski, Robin P. and Claus, Martin (2023) Connecting North Atlantic SST Variability to European Heat Events over the Past Decades. Open Access Tellus A: Dynamic meteorology and oceanography, 75 (1). pp. 358-374. DOI 10.16993/tellusa.3235.

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Abstract

The occurrence of European heat events has increased during the last two decades. European heat events are responsible for social, economic and environmental damage and are projected to increase in magnitude, frequency and duration under global warming, strengthening the interest about the contribution of different mechanisms. Using the ERA5 reanalysis product, we go beyond case studies relating European heat events with cold North Atlantic sea surface temperatures (SSTs), and perform a systematic approach with a composite analysis to investigate the link between North Atlantic SSTs in a domain south of Greenland and the 2m air temperature (T2m) over central Europe. Composites of different North Atlantic SST states show that events with a negative tendency of North Atlantic SSTs are often followed by positive European T2m anomalies during summers when the North Atlantic SSTs are persistently low for several months. Enhanced lower–tropospheric baroclinicity in the North Atlantic is followed during these events by a slantwise ascent and an enhanced upper–tropospheric waveguide, promoting a downstream development of an European ridge. A combination of a wave number 3 pattern and regionally confined Rossby wave activity contribute to a trough–ridge pattern in the North Atlantic–European sector. A composite of European heat events further confirms the lagged statistical relationship between cold North Atlantic SSTs with a negative tendency and positive European T2m anomalies. A negative tendency of North Atlantic SSTs precedes 15 of 18 European heat events, and cold North Atlantic SST conditions are present during 14 of 18 European heat events.

Document Type: Article
Keywords: North Atlantic SST; European heat events; Trough–ridge pattern; Thermodynamical mechanisms; Planetary waves; Rossby wave packets
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-OD Ocean Dynamics
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
Main POF Topic: PT2: Ocean and Cryosphere
Refereed: Yes
Open Access Journal?: Yes
Publisher: Stockholm University Press
Related URLs:
Projects: ROADMAP
Date Deposited: 28 Nov 2023 14:24
Last Modified: 22 Jul 2024 06:53
URI: https://oceanrep.geomar.de/id/eprint/59487

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