Spatiotemporal Consistency Analysis of KMA, JMA, and JTWC Tropical Cyclone Track Records: Inter-Agency Comparison

The western North Pacific is one of the most active regions for tropical cyclone activity worldwide, and the reliability of long-term typhoon best-track data is critical for assessing storm surges and marine disasters along the Korean Peninsula. This study quantitatively analyzed the inter-agency consistency of the center position, central pressure, and maximum sustained wind speed among the KMA, JMA, and JTWC best-track datasets for 1977-2024. Identical tropical cyclones were matched using IBTrACS storm identifiers, and records from the same observation times were compared. This is an inter-agency consistency analysis, not an accuracy validation against independent observations. The results revealed a three-stage characteristic in the KMA-JMA comparison: the records were nearly identical at the reported coordinate resolution during 1977-2000, showed some discrepancies during 2001-2013, and diverged distinctly after 2014, following the introduction of the KMA’s independent reanalysis system. Although positional differences were generally small, distinct discrepancies appeared in specific periods and intensity-related variables, depending on agency-specific listing criteria, analysis systems, and reporting practices. In particular, the comparison of maximum sustained wind speed between JMA and JTWC showed that the difference between the 10-minute and 1-minute averaging periods was the primary structural factor, and the JMA/JTWC wind-speed ratio varied from 1.34 to 0.79 depending on tropical cyclone intensity. The inter-agency wind-speed ratio was close to the conventional conversion factor of 0.88 in the Cat. 1 range, but deviated systematically from 0.88 in the tropical depression and strong typhoon ranges, indicating that a constant conversion factor applied across all intensity ranges can introduce intensity-dependent bias. These results indicate that the choice of the best-track dataset and wind speed conversion method is a major source of uncertainty in storm surge modeling and tropical cyclone climate analysis around the Korean Peninsula and that agency datasets should be selected according to the analysis purpose.