Abstract: Based on the tropical cyclone track dataset in the Northwestern Pacific from China Meteorological Administration, variations in frequencies and intensities of tropical cyclones (TCs) in the western North Pacific, affecting-China tropical cyclones (ACTCs) and landfall ones (LTCs) reaching typhoon intensity during 1957-2004 were studied. Frequencies of strong tropical cyclones showed significant decreasing trends from 1957 to 2004 and the linear trend was much larger when the intensity was strong. There were no increasing or decreasing trends in the ratios of strong tropical cyclones reaching typhoon intensity, while those reaching strong typhoon and super typhoon showed decreasing trends during 1957-2004. The maximum intensities of TCs, ACTCs and LTCs had all decreased during the period of 1957-2004. The mean intensities of TCs and ACTCs illustrated decreasing trends and the mean intensity of LTCs achieving typhoon intensity also showed decreasing trends.

Key words: strong tropical cyclone, affecting China tropical cyclone, landfall tropical cyclone, China