[gradsusr] define variable independent of time

[Jennifer Adams]

Happily combining 'whatever' with 'theother' requires a metadata  
override for one of the two defined variables. The best way to do this  
is not with define but by using fwrite and writing a new descriptor  
file that has a TDEF that matches one of the variables (or it could be  
completely abstract, maybe this would be better to avoid confusion  
later on). If the variables 'whatever' and 'theother' do not vary in  
E, you can use the E dimension to collect them into the same data set  
-- this might make the subsequent comparison a little easier.
--Jennifer




On Sep 12, 2011, at 4:03 AM, Becker, Bernd wrote:

> Jeff,
>
> That is is the really hard part.
> Each item fx and obs describes a chunk of a time series.
> One would have to manually calculate the start and end dates
> with respect to the reference dfile.
>
> If only (and I think Mike explained it a long time ago, and I cannot  
> find the
> email) one could
> set file 1
> set t 2 34
> define whatever
> set dfile 2
> set t 6 39
> define theother
>
> and happily combine whatever with theother.
>
> Think about multimodel ensemble hindcast analysis, trying to composit
> observed phenomena with modelled phenomena that simply
> don't happen simultaneously.
>
> All the best,
> Bernd.
>
>
> --
> Bernd Becker   Climate Impacts Product Development
> Met Office Hadley Centre    FitzRoy Road  Exeter   Devon EX1 3PB   
> United Kingdom
> Tel.: +44 (0) 1392 884511 Fax: +44 (0)870 900 5050
> E-mail:bernd.becker at metoffice.gov.uk - http://www.metoffice.gov.uk/research/our-scientists/seasonal-to-decadal/bernd-becker
> http://www.metoffice.gov.uk/news/releases/archive/2011/weather-game
>
>
>
> From: gradsusr-bounces at gradsusr.org [mailto:gradsusr-bounces at gradsusr.org 
> ] On Behalf Of Jeffrey Duda
> Sent: 10 September 2011 18:41
> To: GrADS Users Forum
> Subject: Re: [gradsusr] define variable independent of time
>
> You can reference the time of a variable when you use it in a  
> statement.  For example, you could do
>
> 'd var.2(time=12Z01JAN1996) - var.3(time=18Z13AUG2010)'
>
> This should help you do what you want to do.
>
> Jeff Duda
>
> On Sat, Sep 10, 2011 at 3:30 AM, Becker, Bernd <bernd.becker at metoffice.gov.uk 
> > wrote:
> Thanks Arlindo,
>
> That would be nice for single numbers.
>
> It as one notch more elaborate:
>
>   'set dfile 2'
>   'set t 2  33'
>   'define obs     = 'var'.2'
>  'set dfile 3'
>   'set t 2  33'
>   'define fx     = 'var'.3'
> file 2 and 3 have different time frames.
>
> d fx-obs
>
> fails.
> And it would be a real bummer to have to calculate the times from  
> one file relative
> to the other file.
>
> Compositing in this way would be really hard.
>
> Enjoy the weekend!
> Bernd.
>
> --
> Bernd Becker   Climate Impacts Product Development
> Met Office Hadley Centre    FitzRoy Road  Exeter   Devon EX1 3PB   
> United Kingdom
> Tel.: +44 (0) 1392 884511 Fax: +44 (0)870 900 5050
> E-mail:bernd.becker at metoffice.gov.uk - http://www.metoffice.gov.uk/research/our-scientists/seasonal-to-decadal/bernd-becker
> http://www.metoffice.gov.uk/news/releases/archive/2011/weather-game
>
>
>
> From: gradsusr-bounces at gradsusr.org [mailto:gradsusr-bounces at gradsusr.org 
> ] On Behalf Of Arlindo da Silva
> Sent: 09 September 2011 17:40
> To: GrADS Users Forum
> Subject: Re: [gradsusr] define variable independent of time
>
> On Fri, Sep 9, 2011 at 12:05 PM, Becker, Bernd <bernd.becker at metoffice.gov.uk 
> > wrote:
>
> Simple question,
> complicated answer:
>
> I would like to composite stuff from several  files.
>
> Each file has its own time and date info in its own .ctl file.
>
> How can I add elements from different such files?
>
> How can I break away from the strict treatment of the time dimension  
> in
> grads?
>
> open file1.ctl
> define a=ave(b,t=1,t=34)
> close 1
> open file2.ctl
> define c= ave(b,t=3,t=9)
> close 2
> etc.
>
> d a+c
> Cannot contour grid - all undefined values
>
>
> Try:
>
> d a(t=1)+c(t=1)
>
>
> -- 
> Arlindo da Silva
> dasilva at alum.mit.edu
>
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>
>
>
>
> -- 
> Jeff Duda
> Iowa State University
> Meteorology Graduate Student
> www.meteor.iastate.edu/~jdduda
> _______________________________________________
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--
Jennifer M. Adams
IGES/COLA
4041 Powder Mill Road, Suite 302
Calverton, MD 20705
jma at cola.iges.org



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