Examination of Typhoon-Wind Profiles Reaching 1,000-m Height over the Southeast China Sea Based on Reanalysis Data Set and Mesoscale Simulation

Abstract

This paper examines the mean wind profiles of tropical cyclones (TCs) toward 1,000-m height with a low-level jet (LLJ) feature over the Southeast China Sea based on the newly released fifth-generation atmospheric reanalysis (ERA5) from the European Center for Medium-range Weather Forecast (ECMWF). The local TC track distributions and the statistical wind-pressure relationship in ERA5 are verified against observations. A mesoscale simulation study of Typhoon Chan-hom provides a basis for close comparison of the LLJ wind features (i.e., jet height and strength) between ERA5 data and simulated results. The composite mean TC wind profiles classified by mean boundary layer wind speed groups (30–50 m/s) are produced based on an ERA5 reanalysis data set, and presented in four quadrants with respect to the storm center. The axially asymmetric properties of composite wind speed profiles are revealed in four quadrants. The composite mean wind speed profiles up to a 1,000-m height including LLJ are then characterized by fitting them to the three wind profile models, i.e., the power-law, the log-law, and the combined power-logarithmic models, for the wind-resistant structural design of supertall buildings. The main contribution of this paper is to propose a quadrant-dependent TC wind profile model considering LLJ features for determining design wind loads on supertall buildings in typhoon-prone coastal areas of China.