The impact of Northern Hemisphere stratospheric final warming (SFW) events on surface air temperature (SAT) in April and May is examined based on the fifth-generation reanalysis data from the European Centre for Medium-Range Weather Forecasts (ERA5) and historical simulations from the Coupled Model Intercomparison Project Phases 6 (CMIP6). In ERA5, early SFWs occur in mid-March and lead to colder SAT in the Arctic, North Atlantic, and the Eurasian hinterland and warmer SAT in the Black Sea–eastern Europe region in April-May, while the anomalous SAT related to late SFWs that occur in early May is nearly the opposite. In addition, the effect of SFWs on SAT over the North Atlantic and Eurasia is more significant in April (May) in early (late) SFW years. The main pathway that SFW affects SAT over North Atlantic and Eurasia is through a tropospheric quasi-barotropic wave train, successively exhibiting anomalous high (low) centers above warmer (colder) SAT. This wave train seems associated with the Northern Annular Mode at 200 hPa in April, indicating its crucial role in linking SFWs and anomalous SAT. Generally, CMIP6 models can well reproduce the onset process of early and late SFWs but fail to capture its impact on spring SAT because of the underrepresentation of the associated Eurasian wave train due to ensemble means. The intercomparison among the models reveals that, models with realistic anomalous tropospheric wave train over Eurasia also simulate better surface impact of SFWs.

stratospheric final warming,Northern Annular Mode,wave train,surface air temperature