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Re: [Phys-L] measuring hurricane strength



On 9/6/2017 1:38 PM, Folkerts, Timothy J wrote: /in part/

"According to Robert Simpson, there are no reasons for a Category 6 on the Saffir-Simpson Scale because it is designed to measure the potential damage of a hurricane to man-made structures. Simpson stated that "...when you get up into winds in excess of 155 mph (249 km/h) you have enough damage if that extreme wind sustains itself for as much as six seconds on a building it's going to cause rupturing damages that are serious no matter how well it's engineered.""
/snip/

That 'no matter how well it's engineered' comment shows a certain unawareness about how structures are designed. Aircraft are designed to meet a limit load, with a certain design multiplier to account for uncertainties about materials and loads.
Buildings are designed to withstand a certain limit wind speed, floor loading  and increasingly a certain applied seismicity. If we wish to have structures designed to withstand air loads applied by 200 mph winds, we most certainly produce such items. As it is we wish engineers to provide the most bang for the buck.
 Onto a second point: attempting to draw a straight regression line through events which occur about every three years on average, but which may occur zero once or twice in a year and thereby to impute a trend to their frequency is a difficulty, I find. Just one cat 5 Atlantic cyclone this year and it can reasonably be held there is no trend  over the last 90 years - unless someone will use considerably better estimator than a best straight line.
Brian W