Characteristics of rainstorm in Fujian induced by typhoon passing through Taiwan Island

Abstract

Based on the typhoon track and intensity data and the precipitation data of typhoon in China during 1961–2020, the overall characteristics of the rainstorm in Fujian caused by typhoon passing though Taiwan Island were studied. More than 80 percent of typhoons passing though the Taiwan Island can bring heavy rain to Fujian. There are 1.5 events of typhoon rainstorm in Fujian every year, and the average annual impact days are 3.0. In terms of spatial distribution, the frequency and intensity of cross-island typhoon rainstorm decrease rapidly from the coastal areas of Fujian to the inland areas, and Zherong, Changle and Jiu xianshan stations in the coastal areas are the high value centers. The typhoon paths of cross-island typhoon rainstorm in Fujian are mainly divided into three categories: landing-Fujian type (including landing-Fujian northeast turning, landing-Fujian middle northbound and landing-Fujian south westbound), landing-Guangdong and Zhejiang type and offshore turning type, among which landing-Fujian type typhoon has the most significant influence(only the landing-Fujian type appears the rainstorm of ≥50 mm·(24 h)⁻¹), and the rainstorm intensity, influence range and asymmetrical structure of the rainstorm are the strongest, the most extensive and the most significant in the landing-Fujian middle northbound path. Based on the NCEP reanalysis data, the comparative analysis of the environmental fields causing the difference of precipitation intensity between the two typhoons landing-Fujian middle northbound and landing-Fujian south westbound shows that: To the landing-Fujian middle northbound track, strong wind speed area on the north side of the typhoon center leads to strong onshore winds, in the role of mountain terrain, piedmont has better convergence and very strong deep vertical upward movement, with better moisture conditions, it can send low high-energy water vapor to the middle, the precipitation dynamics and water vapor conditions are significantly stronger than the landing-Fujian south westbound track, resulting in more typhoon heavy rain.