Interannual Variability of the Tropical Cyclone Landfall Frequency over the Southern and Northern Regions of East Asia in Autumn

摘要

This study focused on the interannual variability of tropical cyclone (TC) activity over the western North Pacific in autumn. The results show that the frequencies of TC landfalls in the southern and northern coastal regions of East Asia are roughly independent, implying that they are affected by different factors and should be studied separately. Further analysis indicates that the frequency of TC landfall in the southern region is closely related to El Nino-Southern Oscillation, which affects both the upper- and lower-tropospheric circulation over the western North Pacific and East Asia and induces changes in the steering flow. By contrast, the frequency of TC landfall over the northern region has a close connection with a teleconnection pattern in the upper troposphere over the Eurasian continent, which seems to be triggered by an anomalous Rossby wave source over the North Atlantic. This teleconnection pattern leads to anomalous meridional winds over the western North Pacific and East Asia and induces significant changes in the steering flow.