The height on the bouys that are used run about 30m which the frictional
effects of land can be assumed to be nil...on land the wind sensors at most
airports sits ~6m of the gorund in which case would yield different wind
speeds. Hurricane tracking software is now incorporating frictional effects
as the storms approach land and do a fairly good job of accounting for
terrian effects.
"Øyvind Seland" wrote in message
...

On the NOAA webpage I noted that the classification on hurricane strength
was based on
wind speed averaged over 1 minute. At least in Europe classification of
wind speeds in extra-tropical
storms call for a 10 minute average. Going from 10 to 1 minute average may
yield a quite large
increase in wind speed, depending on the nature of the storm and terrain.
I suppose for
a tropical storm over ocean, it is probable not that large variation? For
an extra-tropical
storm over hilly terrain, the effect may be going from a strong gale to
close to hurricane wind speed
Are there no agreed on definition of wind speed?



Øyvind Seland