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

Abstract

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 28 years of maximum wind measurements made at coastal and island stations in the western North Pacific were collected and analyzed. Because of problems in measuring and interpreting sustained surface wind speeds, only recorded peak gust values were used. These peak gust values were reduced to a standard anemometer level of 10 m using a power law relationship and then converted to 1 min sustained wind speeds using gust factors representative of an overwater environment. The sample was restricted to cases where it was reasonably certain that the station experienced the cyclone's winds during its passage. The resulting equation,where pc is the minimum sea level pressure (mb) and Vm the maximum sustained (1 min) wind speed (kt), indicates maximum wind speeds that are significantly lower than many previous studies.