Variations in Typhoon Landfalls over China

The inter-annual variability of typhoon landfalls in China is investigated using historical and modern records. A north-to-south anti-correlation in yearly activity is confirmed from the historical records. When activity over Guangdong is high, it tends to be low over Fujian and vice versa. This spatial variation is identified in the modern record using a factor analysis model, which delineates the southern provinces of Guangdong, and Hainan from the northern provinces of Fujian, Taiwan, Zhejiang, Shanghai,Jiangsu, and Shandong. An index of annual activity representing the degree to which each year follows this pattern of activity is used to identify correlated climate variables. A useful model that includes sea level pressure differences between Mongolia and western China and SST over the midlatitude NW Pacific during the summer explains 27% of the inter-annual variability of the index. Physically, we suggest that a stronger than normal north to south pressure gradient increases the surface easterly wind flow over northern China, this coupled with lower SST over midlatitude NW Pacific, favors typhoons taking a more southerly track toward Hong Kong.