Extreme windstorms are the most important natural hazards affecting Europe. Losses are not primarily caused by the sustained wind speed but by the gusts, i.e., the maxima of the wind speed during a few seconds.
A recent paper by Dr Henk van den Brink shows that the vertical profile of the wind gust follows directly from the logarithmic profile of the average wind. Also the uncertainty in the gust estimates can easily be determined from information of the average wind speed at two different heights.
One specification of practical importance is that the maximum 3s-gust in a 10minute period at 10m height is arithmetically equal to the average wind at 140m. At larger heights the gusts are equal to the average wind speed at an easily determinable height that is a factor α (α > 1) higher.
Validation over The Netherlands indicates that this rule applies to heights up to at least 200m. This outcome is validated both over land and over sea, and is independent of surface roughness. The proposed parameterization reproduces the climatological values of the measured extreme wind gusts. Maximum gusts for individual winter months are better represented than for individual summer months. The mean error in the monthly winter maxima estimates is 5%.
Read more here.
