Impacts of four types of ENSO events on tropical cyclones making landfall over mainland china based on three best-track datasets

摘要

Impacts of El Nio Modoki (ENM), La Nia Modoki (LNM), canonical El Nio (CEN) and canonical La Nia (CLN) on tropical cyclones (TCs) that made landfall over mainland China during 1951-2011 are analysed using best-track data from China, the USA and Japan. Relative to cold phase years (LNM and CLN), landfalling TCs in warm years (ENM and CEN) have a farther east genesis location, as well as longer track lengths and durations, both in total and before landfall. ENM demonstrates the highest landfall frequency, most northerly mean landfall position, and shortest after-landfall sustainability (track length and duration), which indicate a more frequent and extensive coverage of mainland China by TCs, but with shorter after-landfall influence. CEN has low landfall frequency and the most southerly mean landfall location. LNM has the most westerly genesis location, being significantly farther west than the 1951-2011 average and leading to short mean track lengths and durations both in total or before landfall, all of which are significantly shorter than the 1951-2011 average. Variations in the low-level wind anomaly, vertical wind shear, mid-level relative humidity, steering flow, the monsoon trough and the western Pacific subtropical high (WPSH) can to some extent account for the features of frequency, location, track length and duration of landfalling TCs. Since ENSO Modoki is expected to become more frequent in the near future, the results for ENSO Modoki presented in this paper are of particular significance.