Distinguishing Impacts on Winter Temperatures in Northern Mid-High-Latitude Continents during Multiyear and Single-Year La Nina a Events: A Modeling Study

Utilizing a 2200-yr CESM1 preindustrial simulation, this study examines the influence fl uence of property distinctions between single-year (SY) and multiyear (MY) La Ni & ntilde;as on their respective impacts on winter surface air temperatures across mid-high-latitude continents in the model, focusing on specific fi c teleconnection mechanisms. Distinct impacts were identified fi ed in four continent sectors: North America, Europe, Western Siberia (W-Siberia), and Eastern Siberia (E-Siberia). The typical impacts of simulated SY La Ni & ntilde;a events are featured with anomalous warming over Europe and W&E-Siberia and anomalous cooling over North America. Simulated MY La Ni & ntilde;a events reduce the typical anomalous cooling over North America and the typical anomalous warming over W&E-Siberia but intensify the typical anomalous warming over Europe. The distinct impacts of simulated MY La Ni & ntilde;as are more prominent during their fi rst winter than during the second winter, except over W-Siberia, where the distinct impact is more pronounced during the second winter. These overall distinct impacts in the CESM1 simulation can be attributed to the varying sensitivities of these continent sectors to the differences between MY and SY La Ni & ntilde;as in their intensity, location, and induced sea surface temperature anomalies in the Atlantic Ocean. These property differences were linked to the distinct climate impacts through the Pacific fi c North America, North Atlantic Oscillation, Indian Ocean-induced wave train, and tropical North Atlantic-induced wave train mechanisms. The modeling results are then validated against observations from 1900 to 2022 to identify disparities in the CESM1 simulation.