East Asian synoptic climatology linked to Atlantic multidecadal variability

The Atlantic Multidecadal Oscillation (AMO) is a climate phenomenon that can be observed in historical data and has potential connections to global synoptic climatic changes. The AMO can be used to predict climate patterns. This study examined how AMO-induced changes in the westerly jet stream over East Asia could affect the climatological distribution of weather patterns. Cluster analyses were conducted to determine how the AMO influences the frequency of cold surges in winter and typhoons in late summer for the period from 1941 to 2021. We observed inverse changes in the frequency of wintertime wave-train versus blocking cold surges during the negative AMO phase, the former increasing and the latter decreasing. This was associated with a southward shift of the upper-tropospheric westerly jet stream. Additionally, the southward shift of the westerly jet stream and a more pronounced wave pattern during late summer had a significant effect on the increase in the frequency of typhoons. These findings suggest that long-term predictions of East Asian synoptic climatology on an AMO timescale may be feasible.