Tropical Cyclone Minimum Sea Level Pressure/Maximum Sustained Wind Relationship for the Western North Pacific

Determining the proper relationship between the minimum sea level pressures and maximum sustained winds in tropical cyclones has been a long standing problem. The major obstacle has been the lack of sufficient ground truth, i.e., actual measurements of maximum wind speeds in tropical cyclones with a wide range of central pressures. In this study, 26 years of maximum wind measurements made at coastal and inland stations in the western North Pacific were collected and analyzed. Because of problems in measuring and interpreting sustained surface wind speeds, only recorded peak gusts values were used. These peak gusts values were reduced to a standard anemometer level of 10 meters using a power law relationship and then coverted to one-minute sustained wind speeds using gust factors representative of an over water environment. The sample was restricted to those cases in which it was reasonably certain that the station experienced the cyclone's maximum winds during its passage. The resulting equation V sub m = 6.7 (1010-P sub c) 0.644 where P sub c is the minimum sea level pressure (mb) and V sub m is the maximum sustained wind speed (knots), indicates maximum wind speeds that are significantly lower than many previous studies. (Author)