The maximum wind radius (R_max) of typhoon is one of the predominant parameters for the estimation of storm surges. The present paper reviewed the existing methods that estimate R_max by either central pressure or maximum wind speed and concluded that all of which would substantially over or underestimate storm surges. It was found that the radius of 50-kt wind (R₅₀) can be alternatively used for the R_max estimation (R_max = 0.23R₅₀). It was also suggested that the variability of R_max should be taken into account in the storm surge simulation in order to minimize estimation errors, considering a couple of different radii. The proposed R_max estimation model using R₅₀ is expected to increase reliability of storm surge prediction to a large extent and would contribute to the disaster risk management particularly in those countries located near Japanese southern ocean basin, such as Japan, China, Taiwan, and the Philippines.

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