[gradsusr] Azimuthally average

[Davide Sacchetti]

then define a circle mask that is 1 inside the circle, undef outside.
d mean(mean(mask*mag(u,v),x=90,x=110),y=90,y=110)
it will work (in this case radius must be less than 5 cells)


Davide



 From:   Sim D. Aberson <sim.aberson at noaa.gov> 
 To:   <gradsusr at gradsusr.org> 
 Sent:   7/1/2020 2:49 PM 
 Subject:   Re: [gradsusr] Azimuthally average 

This is average over a square.  In looking at tropical cyclones, for
example, we want to see the azimuthal average with distance from the
center.  See Hamsu3 and Hamsu4 at
http://rammb.cira.colostate.edu/quarterly_reports/3qtr99/tropica3.htm.
It appears that these were made with GrADS.

Sim

On 7/1/20 4:58 AM, Davide Sacchetti wrote:
> if you can approximate azimuthal average with a "mean of grid points
> values near to your cell" - that is average on a square, not a round
> -suppose your grid coordinate center was 100, 100
> set x 100
> set y 100
> set lev 900 300
> d mean(mean(mag(u,v),x=99,x=101),y=99,y=101)
> 
> hoping it could help
> bye
> Davide
> 
> On Wed, 2020-07-01 at 11:32 +0900, lpasmanoranjan wrote:
>> Hello Davide,
>> Thank you for your answer. I am so sorry for not explaining my
>> question properly.
>> I am looking for the wind speed a location at each level but
>> azimuthally. I am emphasizing azimuthally because wind blows at
>> various speed from different directions around the location. So I
>> need show the azimuthally averaged wind speed.
>>
>> On Wed, Jul 1, 2020 at 0:09 Davide Sacchetti <
>> davide.sacchetti at arpal.liguria.it
> <mailto:davide.sacchetti at arpal.liguria.it>> wrote:
>> > Sorry but I do not understand your question. Are you looking for
>> > wind speed average between 900 and 300 hPa at a fixed location?
>> > If this was the case:
>> > 'set lev 900'
>> > 'd mean(mag(u,v), lev=900, lev=300)'
>> >
>> > bye bye
>> > Davide
>> >
>> >
>> > From: lpasmanoranjan <lpasmanoranjan at gmail.com
> <mailto:lpasmanoranjan at gmail.com>>
>> > To: GrADS Users Forum <gradsusr at gradsusr.org
> <mailto:gradsusr at gradsusr.org>>
>> > Sent: 6/29/2020 11:42 AM
>> > Subject: [gradsusr] Azimuthally average
>> >
>> > > Dear Users,
>> > > I would like to plot a vertical profile of azimuthally average of
>> > > a variable at a location. e.g.
>> > > I have a grid data at 3 km resolution.
>> > > ‘set lat 21.5’
>> > > ‘set lon 82.5’
>> > > ‘set lev 900 300’
>> > > ‘d azimuth_average(mag(u,v)’
>> > >
>> > > Any suggestions or scripts, how to proceed in GrADS?
>> > >
>> > > Thank you.
>> > > _______________________________________________
>> > > gradsusr mailing list
>> > > gradsusr at gradsusr.org <mailto:gradsusr at gradsusr.org>
>> > > http://gradsusr.org/mailman/listinfo/gradsusr
> 
> 
> 
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> 
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-- 
Sim Aberson (he/him/his)
NOAA/AOML/Hurricane Research Division   Miami, FL
https://www.aoml.noaa.gov/hrd/people/simdaberson/
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Attenzione ARPAL ha cambiato indirizzi digitali, i nuovi indirizzi di e-mail sono composti dall'attuale nome.cognome seguito da @arpal.liguria.it, quindi nome.cognome at arpal.liguria.it
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