Tropical Cyclones over the Western North Pacific Strengthen the East Asia-Pacific Pattern during Summer

The contribution of tropical cyclones (TCs) to the East Asia-Pacific (EAP) teleconnection pattern during summer was investigated using the best track data of the Joint Typhoon Warning Center and NCEP-2 reanalysis datasets from 1979 to 2018. The results showed that the TCs over the western North Pacific (WNP) correspond to a strengthened EAP pattern: During the summers of strong convection over the tropical WNP, TC days correspond to a stronger cyclonic circulation anomaly over the WNP in the lower troposphere, an enhanced seesaw pattern of negative and positive geopotential height anomalies over the subtropical WNP and midlatitude East Asia in the middle troposphere, and a more northward shift of the East Asian westerly jet in the upper troposphere. Further analyses indicated that two types of TCs with distinctly different tracks, i.e., westward-moving TCs and northward-moving TCs, both favor the EAP pattern. The present results imply that TCs over the WNP, as extreme weather, can contribute significantly to summer-mean climate anomalies over the WNP and East Asia.

Automated summary

The study revealed that tropical cyclones in the western North Pacific contribute significantly to the East Asia-Pacific teleconnection pattern during summer, enhancing various atmospheric anomalies in the region.