Re: missing values

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Fri Jan 04 2013 - 13:33:09 MST

You can send a clean small script and a sample data file via
ftp. See below.

Also,

   clat = cos(lat*rad)

not sure where you created 'lat' but maybe

    clat = cos(ocean&lat*rad)

would be better

On 1/4/13 12:41 PM, rafael dido wrote:
> Hallo NCL Users,
>
> Thanks for the response,
>
> I meant, why did the result of the areal average either for land masking or
> ocean masking in this case (precipitation over the ocean or land) is equal
> to -999. I noticed in the previous email the the print value for "ave"
> which is an areal average for sea is equal to missing value.
>
> What should i do thus i will obtain the real value of this calculation.
>
> my code
> [snip]
>
> f = addfile("/projekt1/precip_ocean.nc","r") ; Read in first time step
> and
> pocean = f->psea(:,{-10:10},:)
> pocean@_FillValue = pocean@missing_value
> pocean@_FillValue = -999
> printVarSummary(pocean)
>
> rad = 4.0*atan(1.0)/180.0
> clat = cos(lat*rad)
> ocean = dim_avg_Wrap( pocean(lat|:, lon|:, time|:) )
> Ave = wgt_areaave(ocean, clat, 1.0, 1)
> print(ave)
>
> [snip]
>
> --------------------------Result-------------------
> Variable: Ave
> Type: float
> Total Size: 4 bytes
> 1 values
> Number of Dimensions: 1
> Dimensions and sizes: [1]
> Coordinates:
> Number Of Attributes: 1
> _FillValue : -999
> *(0) -999 <------------------------------Areal Average of
> precipitation over the Ocean*
>
>
> Thanks,
> Rafael
>
>
>
>
>
>
>
>
>
>
> On Sat, Jan 5, 2013 at 3:57 AM, Mary Haley <haley@ucar.edu> wrote:
>
>> Rafael,
>>
>> I'm not sure what the problem is. Do you mean that you don't want a
>> _FillValue of -999?
>>
>> If so, then in your script, you changed the _FillValue attribute to have a
>> value of -999, which means when you take the average, it will also
>> have a _FillValue attribute of -999.
>>
>> If you don't want -999 as a _FillValue, then remove this line:
>>
>>
>> pocean@_FillValue = -999
>>
>>
>> --Mary
>>
>>
>> On Jan 4, 2013, at 10:49 AM, rafael dido wrote:
>>
>> Hi NCL,
>>
>> I have nc file containing missing value indicated by "_"
>>
>> dimensions:
>> lon = 360 ;
>> lat = 181 ;
>> time = UNLIMITED ; // (4383 currently)
>> variables:
>> double lon(lon) ;
>> lon:units = "degrees_east" ;
>> lon:modulo = 360. ;
>> lon:point_spacing = "even" ;
>> lon:axis = "X" ;
>> double lat(lat) ;
>> lat:units = "degrees_north" ;
>> lat:point_spacing = "even" ;
>> lat:axis = "Y" ;
>> double time(time) ;
>> time:units = "hours since 1997-01-01 00:00:00" ;
>> time:time_origin = "01-JAN-1997 00:00:00" ;
>> time:axis = "T" ;
>> float psea(time, lat, lon) ;
>> * **psea:missing_value = -1.e+34f ;*
>> * psea:_FillValue = -1.e+34f ;*
>> // global attributes:
>> :Conventions = "CF-1.0" ;
>> data:
>>
>> psea =
>> _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
>> _,
>> _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
>> 0.02250607, 0.5173603, 0, 0, 0, 0, 0, 0, 0, 0.01500405, 0, 0, 0, 0, 0, 0,
>> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>> 0,
>> _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _,
>> _,
>> _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, 0, 0, 0.4348826,
>> 0.05248583,
>> 3.899931, 24.72732, 53.44849, 21.48183, 11.3707, 3.757559, 0.0299919,
>>
>> [SNIP]
>>
>> Once, I calculated the average for a specific domain i got the result is
>> -999 as
>> i set my command as follow:
>>
>> f = addfile("/projekt1/precip_ocean.nc","r") ; Read in first time
>> step and
>> pocean = f->psea(:,{-10:10},:)
>> pocean@_FillValue = pocean@missing_value
>> pocean@_FillValue = -999
>> printVarSummary(pocean)
>>
>> rad = 4.0*atan(1.0)/180.0
>> clat = cos(lat*rad)
>> ocean = dim_avg_Wrap( pocean(lat|:, lon|:, time|:) )
>> Ave = wgt_areaave(ocean, clat, 1.0, 1)
>> print(ave)
>>
>> === [executed]
>> Variable: Ave
>> Type: float
>> Total Size: 4 bytes
>> 1 values
>> Number of Dimensions: 1
>> Dimensions and sizes: [1]
>> Coordinates:
>> Number Of Attributes: 1
>> _FillValue : -999
>> *(0) -999*
>>
>>
>> Is there any hints how to handle this problem in NCL? When I used another
>> language program,
>> and I do not get any problem to calculate this average.
>>
>>
>> Thanks
>>
>> RF.
>>
>>
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>
>
>
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Received on Fri Jan 4 13:33:18 2013

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