Impact of climate change on wintertime European atmospheric blocking
Sara Bacer, Fatima Jomaa, Julien Beaumet, Hubert Gallée, Enzo Le Bouëdec, Martin Ménégoz, Chantal Staquet
Abstract
Abstract. We study the impact of climate change on wintertime atmospheric blocking over Europe focusing on the frequency, duration, and size of blocking events. These events are identified via the weather type decomposition (WTD) methodology applied on the output of climate models of the Coupled Model Intercomparison Project phase 6 (CMIP6). Historical simulations and two future scenarios, SSP2-4.5 and SSP5-8.5, are considered. The models are evaluated against the reanalysis, and only a subset of climate models, which better represent the blocking weather regime in the recent-past climate, is considered for the analysis. We show that the spatio-temporal characteristics of recent-past atmospheric blocking are in agreement with previous studies that define blocking events with blocking indexes. We find that frequency and duration of blocking events remain relatively stationary over the 21st century. We define a methodology that relies on the WTD for the blocking event identification in order to quantify the size of the blocking events, and we find that the blocking size is basically unchanged in the future.