Boreal winter stratospheric climatology in EC-EARTH: CMIP6 version

Abstract The performance of the European Consortium Earth-system model (EC-EARTH) in boreal winter stratosphere is comprehensively assessed for first time, particular its version 3.3 that contributes to CMIP6. A 100-year long simulation with prescribed climatological boundary conditions and fixed radiative forcing, representative present-day climate, used evaluate stratospheric circulation identify biases. Results show EC-EARTH has a large issue vertical distribution temperature from tropics mid-latitudes, seemingly linked processes ozone, leading biased warm middle-upper stratosphere. Associated this bias, simulates stronger polar vortex at upper-stratospheric levels while Brewer-Dobson middle/lower weaker than reanalysis. amplitude planetary waves overall underestimated, but magnitude background wave injection troposphere into overestimated, related lower-stratospheric and, thus, less effective filtering. This bias westerly flow could have contribution parameterized waves. overestimation driving maximum early-winter, may explain overestimated frequency sudden warmings as compared spatial climatology revealed distinctive role waves: large-scale (wavenumbers 1–2) dominate eddy heat flux over North Pacific, small-scale 3–4) are responsible doubled-lobe structure Eurasia. properly feature, although overestimates central