On the representation of atmospheric circulation modes in regional climate models over Western Europe

Atmospheric circulation is a key driver of climate variability, and the representation atmospheric modes in regional models (RCMs) can enhance credibility projections. This study examines large-scale Coupled Model Inter-comparison Project phase 5 RCMs once driven by ERA-Interim, two general (GCMs). The region Western Europe are classified using Promax rotated T-mode principal component analysis. results indicate that replicate as obtained from ERA5 reanalysis, though with biases dependent on data providing lateral boundary condition choice RCM. When provided ERA-Interim more consistent observations, simulated map types associating time series match well their counterparts ERA5. Further, average, multi-model ensemble mean analysed RCMs, indicated slight improvement Conversely, when GCMs without assimilation observational data, modes, ERA5, relatively less accurate compared to ERA-Interim. suggests stem GCMs. On was not improved five either However, best-performed were selected average improvement. Moreover, presence North Atlantic Oscillation (NAO) depends also conditions. relationship between NAO replicated only reanalysis. forcing model main factor reproducing circulation.