MODELING RETURN PERIODS OF TROPICAL CYCLONE INTENSITIES IN THE VICINITY OF HAWAII

Tropical cyclones in the vicinity of Hawaii have resulted in great pro perty damage. An estimate of the return periods of tropical cyclone in tensities is of particular interest to governments, public interest gr oups, and private sectors. A dimensionless quantity called relative in tensity (RI) is used to combine all available information about the tr opical cyclone characteristics at different places and times. To make a satisfactory estimate of the return periods of tropical cyclone inte nsities, a large number of RIs are simulated by the Monte Carlo method based on the extreme value distribution. The return periods of RIs an d the corresponding maximum wind speeds associated with tropical cyclo nes are then estimated by combining the information about the intensit ies and occurrences. Results show that the return periods of maximum w ind speeds equal to or greater than 125, 110, 100, 80, 64, 50, and 34 kt are estimated to be 137, 59, 33, 12, 6.6, 4, and 3. 2 years, respec tively. The Monte Carlo method is also used to estimate the confidence intervals of the return periods of tropical cyclone intensities. The sensitivity test is conducted by removing the portion of the data prio r to satellite observations. For maximum wind speeds less than 80 kt, estimates of return periods from the shorter dataset (1970-95) are alm ost identical to those when the complete duration time series are used (1949-95).