Landfalls of Tropical Cyclones with Rapid Intensification in the Western North Pacific

Abstract. This study statistically investigates the seasonal and decadal variation of tropical cyclones (TCs) underwent rapid intensification (RI) and their landfalling cyclone energy in the western North Pacific using the satellite-era best track data from 1986 to 2017. Totally 31.2 % TCs have underwent at least one RI processes (RI TCs) and 341 made landfalls after RI from 946 historical TCs, using the definition of 95th percentile from the accumulative probability distribution of over-water 24-h TC intensity change. The frequent-occurrence region of RI is found in sea areas to the east of Philippines, and the mean genesis and on-set locations of landfalling TCs underwent RI had westward components compared with the ones did not made landfalls. The Philippine coast, the southern Chinese coast and the coast along the southern Japan are the three main regions affected by the landfalling RI TCs. The coasts in the latter two regions have increased trend of cyclone energy since 1986, which possibly correlates with the poleward migration of the mean latitude where TCs reach their lifetime maximum intensities (LMI). The frequency of the landfalling RI TCs have a significant upward trend with insignificant increase in their LMI, while both the LMI and landfalling cyclone energy by TCs that didn't undergo RI in the western North Pacific show downward trends in the period during 1986–2017. The changes of the LMI distribution in the western North Pacific are related tightly with these two types of TCs with different intensification rates: strong TCs are found become stronger mainly due to more active RI processes, while weak TCs have weakened in majority of moderate intensity TCs, which didn't experience RI processes.