The Spatial and Temporal Characteristics of Tropical Cyclone-induced Rainfall in China During 1960—2003

China is one of the countries which are greatly affected by tropical cyclones (TC), with an average of 7—8 landfalls every year.Because of lack of enough and effective observational data several decades ago, the overall statistical study of TC-induced rainfall is needed.With the gradually increase of observational stations in these years, more and more data are available. The TC-induced rainfall data used is distinguished from the daily rainfall by a subjective way in Shanghai Typhoon Institute.Based on the data of TC landing on China and the relevant induced rainfall from 1960—2003, study is carried out of the climate characteristics of the TC-induced rainfall.Results show that, TC rainfall occurs from May to November, with the most active period from July to September, associated with the TC landfall activities.TC rainfall increases in intensity and region from May to August, and then decreases to November, and the TC rainfall reach zenith in volume and coverage in August. Spatial distribution of the TC rainfall and the frequency of TC rainstorms illustrate that they decrease dramatically northwards and inlandwards with the maximum in Hainan Province and the coastal areas of South China and Southeast China. And the ratios of summer TC rainfall to summer total rainfall and TC yearly rainfall to total yearly rainfall in these regions are also highest.Commonly, the TC-induced rainfall is much more in coastal areas than in inland areas.While under advantageous circulation, also, extremely intensive rainstorms can occur somewhere inlands.Statistics shows that the relationship between TC rainfall and TC intensity is not strictly linear, probably because of the complexity of influencing factors on the TC rainfall.Averagely, the mean of TC-induced maximum process rainfall is largest in August and September, and the frequency of TC-induced rainstorms is most in July and August.And the induced rainfall varies with the location where TC land on.The TC which land on Fujian bring about more process rainfall and rainstorms than on the other provinces.TC rainfall in most TC-affected areas in China decreases wavily since 1960, and the intensity of trend is different in target regions. The rainfall volume of decrease is most in South China, and the trend of decrease is most prominent in southwestern part of Northeast China, the western part of Southwest China, the coastal areas of East China and parts of South China.