Comparison of Tropical Cyclone Wind Radius Estimates between the KMA, RSMC Tokyo, and JTWC

Abstract This study compared estimates of gale-force wind radii (R30 or R34) and storm-force (R50) tropical cyclones (TC) by three agencies—the Korea Meteorological Administration (KMA), the Regional Specialized Center (RSMC) Tokyo, Joint Typhoon Warning (JTWC)—in western North Pacific during 2015–2018 investigated characteristics these estimates. The results showed that KMA’s R30 R50 were smaller (38% 29%, respectively) than those RSMC larger (11%) for (12%) JTWC. differences between agencies seem to be largely determined whether agency based only on a TC’s own winds TC combined with other mid-latitude synoptic systems make warnings more comprehensive. former is mainly practice KMA JTWC, whereas latter Tokyo. factors considered estimating also differ agencies: heavily relies intensity—the higher intensity, radius—while Tokyo JTWC rely less intensity but additionally consider latitude storm translation speed in their estimations. In particular, explains why estimated exhibit, average, greater asymmetries (i.e., longest shortest radii) KMA. findings agency-dependent radius data help better determining understanding impact areas risk reduction management.