[gradsusr] Using maskout function to apply TWO masks

[Gargi Akhoury]

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
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>>
>>
>>
>> --
>> Jeff Duda
>> Graduate research assistant
>> University of Oklahoma School of Meteorology
>> Center for Analysis and Prediction of Storms
>>
>> _______________________________________________
>> gradsusr mailing list
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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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