Statistical analysis of extreme wind speeds in Hong Kong and Macau

Abstract

This paper describes a statistical extreme wind analysis for Hong Kong and Macau. An analysis of wind speed records in Macau was recently carried out by one of the authors in relation to the revision and update of the Macau Wind Code Provisions from the 1996 version. The anemometer stations chosen for Macau are located on hills and the records are affected by the surrounding topography and buildings. Anemometer correction for the wind speed changes is carried out in the wind tunnel with topography models of Macau and Taipa. Corrected record of hourly mean wind speeds from 1952 to 2005 is subjected to extreme value analysis. A number of methods are attempted and they include selections of annual maximum or storm wind speeds, use of the V or V2 data, and standard Gumbel or Lieblein BLUE methods. In this paper, the same analysis is applied to the Waglan Island wind data of Hong Kong from 1975 to 2005. All mean wind speeds are corrected to the standard condition of strong wind blowing over the sea surface and at a height of 250 m. This paper also repeats the analysis for Macau wind records incorporating a number of improvements. The resulting extreme wind speeds for Hong Kong and Macau generally have similar values at different return periods. Confidence limit analysis is carried out to recommend safe extreme wind speeds to design for strong wind conditions. The resulting 50-year return mean wind speed is 52.0 m/s for Waglan and 50.7 m/s for Macau. This paper also attempts to recommend wind directionality factors for Hong Kong and Macau.