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The best track data of tropical cyclones (TCs)provided by Regional Specialized Meteorological Center (RSMC)Tokyo for the South China Sea (SCS)from 1977 to 2007 are employed to study the spatiotemporal variations (for a period of 12 hours)and the rapid (slow)intensification (RI/SI)of TCs with different intensity.The main results are as follows.(1)Over this period, the tropical storms (TSs)and severe tropical storms (STSs)mostly intensify or are steady while the typhoons (TYs)mostly weaken.The stronger a TC is initially, the more observation of its intensification and the less its variability will be; the more observation of its weakening is, the larger its variability will be.(2)The TC intensifies the fastest at 0000UTC while weakening the fastest at 1200 UTC.(3)In the intensifying state, TSs, STSs, and TYs are mainly active in the northeastern, central-eastern, and central SCS respectively.The weakening cases mainly distribute over waters east off Hainan Island and Vietnam and west off the Philippines.Some cases of TSs and STSs weaken over the central SCS.(4)The RI cases form farther south in contrast to the SI cases.The RI cases are observed in regions where there are weaker vertical shear and easterly components at 200 hPa.The RI cases also have stronger mid-and lower-level warm-core structure and smaller radii of 15.4 m/swinds.The SI cases have slightly higher SST.