Tropical Atlantic Variability (TAV) in sea surface temperature (SST) exerts a significant influence on the climate of surrounding regions. The Atlantic Niño (ATLN) is one of the leading modes of TAV, with a primary peak in summer (June-July) and a secondary peak in early winter (November-December). This study aims at exploring the atmospheric response to winter ATLN, as it has been much less documented than the summer ATLN. Coupled and atmosphere-only simulations with the climate model EC-EARTH have been performed and analyzed to investigate the extratropical teleconnection of the winter ATLN in the North Atlantic-European (NAE) sector. Results show a tropical Gill-type structure, baroclinic and symmetrically straddling the equator, whose amplitude increases from November-December to January-February. In the extratropics, the atmospheric circulation displays a wave-like dipolar structure with cyclonic anomalies at mid-latitudes and anticyclonic anomalies at subpolar latitudes, which is different from the North Atlantic Oscillation. This wavetrain response includes the feedback from both stationary and transient eddy activity. The associated precipitation anomalies show a robust signal over NAE. Differences in statistical significance are found when comparing observational data with model results, although the spatial patterns are similar, particularly in early winter. These findings enhance our understanding of the potential impact of the winter ATLN and suggest it could represent an untapped source of predictability.

https://journals.ametsoc.org/view/journals/clim/39/15/JCLI-D-25-0164.1.xml