Averaging wind speed in tropical and extra-tropical storms
 

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

Averaging wind speed in tropical and extra-tropical storms
 

Would you stand out in 135mph winds for 10mins? :)

"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

Averaging wind speed in tropical and extra-tropical storms
 

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

Averaging wind speed in tropical and extra-tropical storms
 

I'm not sure which buoys you are talking about here,
but the NOAA ones have sensors nowhere near 30m. More
like 10 at most -- and those are the big disc buoys
in the middle of the gulf.

See, for example

http://www.ndbc.noaa.gov/station_page.php?station=42001
http://www.ndbc.noaa.gov/station_page.php?station=42003


Scott

Shawn Delaney wrote:
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

Averaging wind speed in tropical and extra-tropical storms
 

Sorry, use to looking at the Keys.

"Scott" wrote in message
...

I'm not sure which buoys you are talking about here,
but the NOAA ones have sensors nowhere near 30m. More
like 10 at most -- and those are the big disc buoys
in the middle of the gulf.

See, for example

http://www.ndbc.noaa.gov/station_page.php?station=42001
http://www.ndbc.noaa.gov/station_page.php?station=42003


Scott

Shawn Delaney wrote:
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

Averaging wind speed in tropical and extra-tropical storms
 

On Thu, 22 Sep 2005 23:16:39 GMT,
Shawn Delaney , in
wrote:
+ 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.

The standard observation height at the surface is 10m.

Some buoys have 10m masts. Most are 3m masts, and the data is adjusted
to 10m.

Ships can have variable height instrument packages. Also, a ship's
profile can influence the wind speed/direction measurements.

James
--
Consulting Minister for Consultants, DNRC
I can please only one person per day. Today is not your day. Tomorrow
isn't looking good, either.
I am BOFH. Resistance is futile. Your network will be assimilated.