[gradsusr] Using maskout function to apply TWO masks

Fri Jul 4 05:16:14 EDT 2014

Hello,
     sure.....actually ve data of 65 years n ve to prepare a
climatology......data are in "kelvin" n ve to make it in deg. cel.
My problem is whenever m plotting with kelvin data m getting different
plots for the 12 months, but when m plotting it by writing the command
"define temp=temp-273.15"....m getting the same plot for every month.

On Fri, Jul 4, 2014 at 12:05 PM, Andrew Friedman <andfried at berkeley.edu>
wrote:

> Hi Gargi,
> Can you please post more specific information about the data you’re
> working with?
> Andrew
>
> On Jul 3, 2014, at 9:51 PM, Gargi Akhoury <gargiakhoury at bitmesra.ac.in>
> wrote:
>
> > how to define temperature in degree cel. in gs file or ctl file??
> >
> >
> > On Fri, Jul 4, 2014 at 9:52 AM, Gargi Akhoury <
> gargiakhoury at bitmesra.ac.in> wrote:
> > I am trying to plot 65 years monthly temperature data (climatology
> data), but m getting same plot for every month.what should I do?
> >
> >
> > On Thu, Jul 3, 2014 at 10:10 PM, Roberto Mera <RMera at ucsusa.org> wrote:
> > Yes! that worked! Thanks!
> > From: gradsusr-bounces at gradsusr.org [gradsusr-bounces at gradsusr.org] on
> behalf of Jeff Duda [jeffduda319 at gmail.com]
> > Sent: Thursday, July 03, 2014 12:35 PM
> >
> > To: GrADS Users Forum
> > Subject: Re: [gradsusr] Using maskout function to apply TWO masks
> >
> > I just used 'hgtsfc' as an example of the topography field.  Most models
> have this field.  For your purposes, change it to 'ht'.  Also, swap the
> sign of the mask field to get the logical negation to become the mask.
>  Remember, the maskout function masks areas where the mask field is
> non-positive.  So if you want a part of a field to remain after masking,
> make sure it's in a region where the mask will be positive.  If a point is
> at 1000 m alititude, you want the mask to be nonpositive at that point, so
> something involving 1000, 700, and subtraction needs to result in a
> negative value.  700 - 1000 would do that, so that's 700 - ht for your mask.
> >
> > Jeff Duda
> >
> >
> > On Thu, Jul 3, 2014 at 11:16 AM, Roberto Mera <RMera at ucsusa.org> wrote:
> > Jeff,
> >
> > Thanks for the help. I'm a little confused about this part:
> >
> > maskout(temperature,hgtsfc+700 - height)
> >
> > What is hgtsfc. Is that a defined variable?
> >
> > The temperature and topography variables are in different files so all I
> need is to create a mask about 700m. My ocean mask works.
> >
> > The name of the variable in the topography file is ht. I was trying this:
> >
> > msk700=(ht/ht,ht-700) but it masked out everything below 700 m.
> >
> > Thoughts?
> >
> > Robert
> > From: gradsusr-bounces at gradsusr.org [gradsusr-bounces at gradsusr.org] on
> behalf of Jeff Duda [jeffduda319 at gmail.com]
> > Sent: Tuesday, June 03, 2014 5:09 PM
> > To: GrADS Users Forum
> > Subject: Re: [gradsusr] Using maskout function to apply TWO masks
> >
> > The const() and maskout() are powerful functions suited just for this
> purpose.
> >
> > 'define oceanmaskedtemperature = maskout(temperature,landseamask)' will
> get your your ocean mask
> > 'set lev 1000 900'
> > 'define 700mmaskedtemperature = maskout(temperature,hgtsfc+700 -
> height)' will maskout the grid above 700 m.  Note you need to define this
> in a 3D environment, hence the 'set lev' command preceeding it. Finally,
> > 'd 0.5*(oceanmaskedtemperature + 700mmaskedtemperature)' will give you
> the field you seek.  Adding grids that have undefined values is the same
> thing as taking the intersection of sets.  The 0.5 factor is used because
> the temperature values will get added together where both fields have
> non-missing values.  But those values will be the same, so divide by 2 to
> restore the original values.
> >
> > Jeff Duda
> >
> >
> > On Tue, Jun 3, 2014 at 3:14 PM, Roberto Mera <RMera at ucsusa.org> wrote:
> > Grads crew:
> >
> >
> >
> > I would like to get the area average for the temperature for the
> California Central Valley. I would also like to mask out the ocean so I
> don’t get those temperatures when I take the average. Right now I have a
> script that masks out the ocean and I have also adapted it for other
> purposes.
> >
> >
> >
> > My question is this: How do I apply two masks?
> >
> >
> >
> > I want to mask out the ocean and also, say >700 m altitude.
> >
> >
> >
> > Right now my script loops through ensemble members and calculates the
> time average within each ensemble member and it gives me a number for the
> area average:
> >
> >
> >
> > *mskgrd=maskout(ht/ht,ht-0.1) ****this masks out the ocean
> >
> > count = 1
> >
> > while (count < 18)
> >
> > 'set e 'count
> >
> >
> 'areal=aave(maskout(ave(field88,t=1,t=6),mskgrd(t=1)),x=147,x=250,y=94.1815,y=182.057)'
> >
> > 'd areal'
> >
> > areal=subwrd(result,4)
> >
> > say areal
> >
> > if (rc != 0) ; break ; endif
> >
> > count = count +1
> >
> > endwhile
> >
> >
> >
> > Robert
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
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> >
> >
> >
> >
> > --
> > Jeff Duda
> > Graduate research assistant
> > University of Oklahoma School of Meteorology
> > Center for Analysis and Prediction of Storms
> >
> > _______________________________________________
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> >
> >
> >
> >
> > --
> > Jeff Duda
> > Graduate research assistant
> > University of Oklahoma School of Meteorology
> > Center for Analysis and Prediction of Storms
> >
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> >
> >
> >
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