Autumn Tropical Cyclones over the Western North Pacific

Based on best track data (1949-2016) of tropical cyclones (TCs) provided by the Shanghai Typhoon Institute, China Meteorological Administration (CMA-STI), as well as TC size dataset (1980-2016) derived from geostationary satellite infrared images, autumn TCs over Western North Pacific (WNP) are analyzed, in terms of its genesis frequency, intensity, outer size, landfall features as well as temporal and spatial evolution characteristics. The results show that the top 8 strongest TCs are all autumn TCs in the past 68 years. It accounted for 41.7% of annual total number, slightly less than that of summer TC (43.2%), the frequency of strong typhoons and super typhoons of autumn TCs are higher than that of summer TCs. For all the autumn TC samples, the proportion of super typhoons is the highest (28.5%), which is close to 1/3 of the total genesis frequency. Autumn TCs are characterized by strong typhoons and super typhoons. The proportion of TCs in autumn and the TCs in summer showed an inverse relationship. Statistically speaking, the average R34 of autumn TC increases with the TC intensity scale, indicating the outer size of autumn TC becomes larger when it intensifies. Two genesis centers are observed over the WNP: northeastern South China Sea and east of the Philippines from 130 °E to 150 °E, respectively. From 1949 to 2016, 160 autumn TCs made landfall in China, with an average annual number of 2.4. Autumn TCs are most likely to make landfall in Guangdong province, followed by Hainan province