Decadal variations of intense tropical cyclones over the western North Pacific during 1948–2010

Using Joint Warning Typhoon Center (JTWC) best track data during the period 1948–2010, decadal and interdecadal changes of annual category 4 and 5 tropical cyclone (TC) frequency in the western North Pacific basin were examined. By allowing all of the observed TCs in the JTWC dataset to move along the observed TC tracks in a TC intensity model, the annual category 4 and 5 TC frequency was simulated. The results agreed well with observations when the TC intensity prior to 1973 was adjusted based on time-dependent biases due to changes in measurement and reporting practices. The simulated and adjusted time series showed significant decadal (12–18 years) variability, while the interdecadal (18–32 years) variability was found to be statistically insignificant.