[gradsusr] Problem obtaining daily climatology

Jennifer Adams jma at cola.iges.org
Wed Dec 8 08:53:27 EST 2010


The 'modify' command does not calculate a daily climatology, and there  
is no way to do that directly in GrADS. You must use your own code and  
make decisions about how to handle leap days, filtering, and other  
complications.
--Jennifer

On Dec 8, 2010, at 4:23 AM, krishnamohan wrote:

>
> Hai,
>
> I was calculating daily climatology for 30 year ncep wind from 1979  
> to 2008 and i encountered a problem. As per grads tutorial i have  
> given the following commands
>
> 'reinit'
> 'sdfopen /media/MEGA2/wind/ncep/uwind/level/u200/u200-1979-2009.nc'
> 'set grads off'
> 'set lat -20 40'
> 'set lon 30 180'
> 'set map 1 1 8'
>
> 'set t 1 365'
> 'define uclim = ave(uwnd, t+0,t+10958,365)'
>
> and i am getting uclim properly
>
> but inorder to make it a climatological variable i used 'modify'  
> function
>
> 'modify uclim seasonal'
>
> then i got error
>
> MODIFY Error:  Invalid time scaling in defined variable, then i used
>
> 'modify uclim diurnal'
>
> will say 'Defined variable is now climatological' but is showing  
> same pattern for all the days
>
> As grads tutorial says
>
> seasonal   - For creating monthly or multi-monthly climatologies
> diurnal    - For creating climatologies over a time period less than  
> a day
>
> ie there are only options for monthly or less than a day  
> calculation. what is the option for finding daily climatology using  
> this method
>
>
> -- 
> Krishnamohan.K.S
> Junior Research Fellow
> Department Of Atmospheric Sciences
> Cochin University of Science and Technology
> Cochin,India
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr

--
Jennifer M. Adams
IGES/COLA
4041 Powder Mill Road, Suite 302
Calverton, MD 20705
jma at cola.iges.org



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