Intercomparison of Long-Term Trends in “Violent Typhoons” among Multiple Tropical Cyclone Datasets

抄録

Long-term trends in the frequency of “Violent Typhoons”, which were defined as tropical cyclones with a 10-min maximum sustained wind speed (MSWS) of 54 m s⁻¹ or higher in the western North Pacific, were investigated during 1977-2021. Four datasets were used: the Regional Specialized Meteorological Center (RSMC) Tokyo best-track data, RSMC-Tokyo Dvorak reanalysis data, and two datasets from the Joint Typhoon Warning Center (JTWC) best-track data. One JTWC dataset includes the 10-min MSWS converted from the 1-min MSWS using a factor of 0.88 throughout the periods, and the other includes the 10-min MSWS converted using empirical equations before 1987 and Dvorak conversion tables afterwards. The results showed that the statistical significance of the long-term trend was not found in all datasets for the same analysis period. After 1987, the 10-year average number of Violent Typhoons differed substantially between the RSMC-Tokyo dataset and the JTWC dataset converted using 0.88. However, the Dvorak reanalysis data and the JTWC dataset with the other conversion method were closer to the RSMC-Tokyo dataset. Given the variability among the datasets analyzed, it was not possible in this study to find any robust long-term trends of Violent Typhoons.