Toward Objective, Standardized Intensity Estimates from Surface Wind Speed Observations

Improved extreme wind speed estimation for wind engineering applications

“…This assumption included the grouping of stations into superstations that had drastically different roughness characteristics such as those from urban centers to more open airporttype exposures (Simiu et al, 2003). The assumption that the terrain exposure is open, when applied to airport stations where it is in fact not correct, can lead to 40% to 50% differences or higher (Masters et al, 2010). Both the moving of anemometers and roughness changes over time can cause significant errors if not accounted for Gatey (2011).…”

“…Due to differences in anemometer response and block and moving average techniques, coupled with the non-uniformity of terrain at weather stations, the conversion factor between a 5 s and 3 s gust was shown to exhibit significant variability, the neglect of which can lead to differences approaching a factor of two in some cases (Miller, 2007;Masters et al, 2010). In Australia and other locations (Miller et al, 2011), the ''peak'' wind gust recorded by the Dines anemometer, which may have been responsible for the somewhat arbitrary 3 s value used in codes and standards, is significantly higher ( E15%) than a 3 s moving average gust recorded by cup anemometry.…”

“…This variability may be due to the natural variation in the gustiness of the wind over time scales of approximately 1 min to 5 min and/or to non-stationary wind conditions (e.g., thunderstorms) that are not properly taken into account by using traditional methods such as the Durst curve. Using one representative value of gust factor could be problematic when considering the ''peak'' wind speed for structural design, given that gust factors themselves show considerable variability and may differ by storm type (Masters et al, 2010;Lombardo, 2009). Nevertheless, these available sources of information can and should be exploited.…”

“…These highresolution platforms can capture extreme wind speeds not taken into account for in previous analyses due to the small spatial and temporal scales characterizing the data. In addition, many ASOS records specifically indicate storm types ) and can be used for accurately estimating terrain roughness (Masters et al, 2010). Finally, improved statistical methods are available for the estimation of extremes.…”

Changes of the prevailing trade winds over the islands of Hawaii and the North Pacific

“…The topography [Masters et al, 2010]. Therefore, when parameters for logarithmic wind profile equations such as zero plane displacement and roughness coefficients are unknown, equation (1) …”