Articles | Volume 4, issue 4
Research article
06 Nov 2023
Research article |  | 06 Nov 2023

Cold wintertime air masses over Europe: where do they come from and how do they form?

Tiina Nygård, Lukas Papritz, Tuomas Naakka, and Timo Vihma

Data sets

ERA5 hourly data on single levels from 1940 to present H. Hersbach, B. Bell, P. Berrisford, G. Biavati, A. Horányi, J. Muñoz Sabater, J. Nicolas, C. Peubey, R. Radu, I. Rozum, D. Schepers, A. Simmons, C. Soci, D. Dee, and J.-N. Thépaut

NAO index NOAA/National Weather Service

AO index NOAA/National Weather Service

GBI index NOAA/National Weather Service

Short summary
Despite the general warming trend, wintertime cold-air outbreaks in Europe have remained nearly as extreme and as common as decades ago. In this study, we identify six principal cold anomaly types over Europe in 1979–2020. We show the origins of various physical processes and their contributions to the formation of cold wintertime air masses.