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This paper uses monthly surface air temperature (SAT) data from the Climatic Research Unit dataset and the Coupled Model Intercomparison Project phase 6 multimodel ensemble simulations to investigate the variations in the annual‐mean and four seasons SAT across the Eurasian and North Africa landmasses and the possible causes. The SAT over multiple timescales has significant seasonal and regional differences. The trend, variance of decadal variation (DV), and variance of interannual variability (IV) show that the differences between Siberia and mid‐low latitudes are much larger in winter and spring than in summer and autumn. The SAT exhibits a robust warming trend over Siberia in winter (0.21–0.42°C·decade−1) than over mid–low latitudes in summer (<0.07°C·decade−1). The cause is the combined diversity effects of greenhouse gases (GHG) and anthropogenic aerosols (AA) in four seasons over different regions. The warming trend of Siberia in winter is affected by the combination of strong warming effect by GHG and the weak cooling effect by AA, and the trend of mid–low latitudes in summer is opposite. The leading modes of the DV show a consistent spatial pattern over the whole Eurasia in four seasons while the IV show a meridional dipole pattern across 40°N except in summer. The internal climate variability is the main driver of the SAT IV and DV, but the effect of anthropogenic activity and natural forcing may reinforce the IV and DV in some regions. The combined role of GHG and AA forcings can significantly enlarge the DV in many parts of Eurasia, and the AA and natural forcing have significant effect on the IV in the high latitudes. [ABSTRACT FROM AUTHOR]

Previous studies indicated that El Niño–Southern Oscillation (ENSO) significantly impacts the zonal shift of the South Asian High (SAH) in boreal summer. This analysis reveals that the influence of ENSO on the zonal shift of the SAH has experienced a significant interdecadal weakening around the early 1980s. Specifically, ENSO has a significant relation with the SAH's zonal shift before the early 1980s. However, after the early 1980s, the impact of the ENSO on the SAH is weak. We further examined the physical processes for the interdecadal change of the ENSO–SAH relation. It is indicated that interdecadal change of relationship between ENSO and SAH zonal shift is attributable to change in the connection between ENSO and Indian summer monsoon (ISM). Before the early 1980s, ENSO could exert significant impacts on the ISM and lead to significant condensational latent heating anomalies around the northern Indian Peninsula. The atmospheric heating anomalies around the northern Indian Peninsula trigger an atmospheric wave train extending eastward from North Africa toward the Iranian Plateau (IP), which further leads to changes in the zonal location of the SAH. Hence, the ENSO exerts significant impacts on the summer SAH zonal shift. By contrast, after the early 1980s, ENSO had a weak impact on the ISM and could not lead to apparent atmospheric heating anomalies over IP. As such, ENSO has a weak effect on the SAH zonal shift. Further analysis indicates that interannual variation of the SAH zonal shift is related to an atmospheric wave train over mid–high latitudes of Eurasia after the early 1980s. [ABSTRACT FROM AUTHOR]