Abstract:Based on the optimal typhoon track data of China Meteorological Administration (CMA) in 1979-2023, the National Meteorological Centre (NMC) real-time typhoon track and intensity data in 2024 and the monthly ERA5 reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF), we analyze and reveal the different features of typhoons generated over western North Pacific in summer and autumn of 2024 from the following three aspects: their generation, activity and landfall. The results show that the number of typhoons formed in western North Pacific in the summer of 2024 was smaller than normal, their generation sources were more northward and eastward, and their maximum intensities were weaker. No typhoons were generated in the early summer from 1 June to 18 July, but typhoons occurred frequently in midsummer, mostly following northwest- and north-direction tracks. The typhoons making landfall in China were fewer than usual, and their landfall intensities were relatively weak. However, they were more active in autumn. The number of the autumn typhoons ranked the third highest in history, their generation sources were more northward and westward, and their intensities were unusually strong. The autumn typhoon activities were characterized by distinct periodicity and clustering, with most following the westward or northwestward tracks. The number of landfall typhoons was significantly above the normal, and at the same time their landfall intensities were above the average. Further analysis suggests that the significant differences between the summer and autumn typhoons in 2024 were closely correlated to the multiple factors including the lag effect of sea surface temperature in the year following El Nino, the abnormal western North Pacific subtropical high, the phase transition of the Madden-Julian oscillation, the onset and withdrawal of summer monsoon in the South China Sea, and so on.