关键词: 重现期, 最大风速, 极值I型分布, 皮尔逊-III型分布, 上海

Abstract:

Strong wind is defined as the instantaneous wind speed (also called maximum wind speed) at or above 17.0 m/s in meteorology. Strong wind is a disastrous weather phenomenon, it often causes agricultural disaster, house and wall destroyed and casualties and property losses. Therefore, it is quite useful and necessary to understand the characteristics of strong wind, and their impacts for the purpose of development of social economy and resource environment protection. Based on the historical wind speed observation data from 11 stations in Shanghai, the temporal changes of maximum wind speed for different recurrence intervals in urban areas of Shanghai during 1901-2011 and the spatial distributions of maximum wind speed for different recurrence intervals in suburbs and exurbs of Shanghai during 1974-2011 were estimated in this paper with extreme value type I distribution (EV-I) and Pearson type III distribution (P-III). Furthermore, the extreme wind speeds with different recurrence intervals were also estimated in each county of Shanghai during 1974-2011 based on the maximum wind speeds with different recurrence intervals estimated by P-III distribution and a gustiness factor of 1.7. The results indicate that the maximum wind speeds with a recurrence interval of 10, 30, 50 and 100 years are 21.0, 24.9, 26.7 and 29.2 m/s respectively with the estimation of extreme value type I distribution, and they are 20.9, 24.4, 26.0 and 28.0 m/s respectively with the estimation of P-III distribution in Shanghai during 1901-2011. In comparison, the fitting precision of extreme value type I distribution is better than that of P-III distribution in urban areas of Shanghai during 1901-2011. Under the impacts of regional rapid urbanization and the reduced intensity of cold waves and the decreased number (and decreased intensity) of land-falling typhoons caused by global climate change, the maximum wind speed has decreased by approximately 0.8 m/s per decade in Shanghai during 1901-2011. During 1974-2011, the maximum wind speed with a recurrence interval of 10 years is the greatest in Jinshan, and the maximum wind speeds with a recurrence interval of 30, 50 and 100 years are the greatest in Nanhui or Pudong. For each county, the fitting precision of P-III distribution is better than that of extreme value type I distribution during 1974-2011. The maximum wind speeds with a recurrence interval of 10, 30, 50 and 100 years are 19.0, 21.4, 22.6 and 24.1 m/s respectively at a height of 10 m with the estimation of P-III distribution. The extreme wind speed with a recurrence intervals of 10 is the greatest in Jinshan, and the extreme wind speeds with a recurrence interval of 30, 50 and 100 years are the greatest in Nanhui. The extreme wind speeds with a recurrence interval of 10, 30, 50 and 100 years are 32.3, 36.4, 38.4 and 41.0 m/s respectively at a height of 10 m. Overall, the maximum wind speed and extreme wind speeds for different recurrence intervals are the least in urban areas, and they are the greatest in the southern coastal areas of Shanghai.

Key words: recurrence interval, maximum wind speed, extreme value type I distribution (EV-I), Pearson type III distribution (P-III), Shanghai