[ncl-talk] Save output as a NetCDF or tiff file

Setareh Rahimi setareh.rahimi at gmail.com
Mon Nov 13 23:45:24 MST 2023


Thank you for your help! but I still receive this error :

fatal:Variable (XLAT) is undefined

fatal:["Execute.c":8637]:Execute: Error occurred at or near line 186 in
file aod


fatal:Variable (XLONG) is undefined

fatal:["Execute.c":8637]:Execute: Error occurred at or near line 187 in
file aod



On Tue, Nov 14, 2023 at 4:27 AM Dennis Shea <shea at ucar.edu> wrote:

> By netCDF definition, a coordinate variable must be one-dimensional:
>
> The XLAT, XLONG variables are three dimensional.
>
> Time | 24] x [south_north | 229] x [west_east | 219]
>
> As with the WRF files, these must be written as regular variables.
>
>      ncdf->XLAT     = XLAT
>      ncdf->XLONG = XLONG
>
> Most commonly, the XLAT/XLONG variables do not vary with time. Hence some
> users just write the initial values as a two-dimensional variable
>
>      ncdf->XLAT     = XLAT(0,:,:)
>      ncdf->XLONG = XLONG(0,:,:)
>
>
>
> On Mon, Nov 13, 2023 at 1:21 AM Setareh Rahimi <setareh.rahimi at gmail.com>
> wrote:
>
>> Thanks Dennis, but the page is not available!
>>
>> On Mon, Nov 13, 2023 at 2:58 AM Dennis Shea <shea at ucar.edu> wrote:
>>
>>> See copy_VarCoords
>>>
>>> On Fri, Nov 10, 2023 at 1:39 PM Setareh Rahimi <setareh.rahimi at gmail.com>
>>> wrote:
>>>
>>>> Thank you so much for your help. How can I assign lat/lon to the AOD,
>>>> please?
>>>> I used the below lines in the script but received the following error:
>>>> " fatal:(XLAT) is not a named dimension in variable (a2)".
>>>>
>>>>
>>>>
>>>>        system("/bin/rm -f AOD550_2D.nc")    ; remove any pre-existing
>>>> file
>>>>
>>>>        ncdf = addfile("AOD550_2D.nc" ,"c")  ; open output netCDF file
>>>>
>>>>
>>>>
>>>> ;===================================================================
>>>>
>>>>     ; create global attributes of the file (optional)
>>>>
>>>>
>>>> ;===================================================================
>>>>
>>>>        fAtt               = True            ; assign file attributes
>>>>
>>>>        fAtt at title         = "Derived AOD"
>>>>
>>>>        fAtt at creation_date = systemfunc ("date")
>>>>
>>>>
>>>>        fileattdef( ncdf, fAtt )            ; copy file attributes
>>>>
>>>>
>>>>
>>>> ;===================================================================
>>>>
>>>>     ; make time an UNLIMITED dimension; recommended  for most
>>>> applications
>>>>
>>>>
>>>> ;===================================================================
>>>>
>>>>        filedimdef(ncdf,"time",-1,True)
>>>>
>>>>
>>>>
>>>> ;===================================================================
>>>>
>>>>     ; output variables directly; NCL will call appropriate functions
>>>>
>>>>     ; to write the meta data associated with each variable
>>>>
>>>>
>>>> ;===================================================================
>>>>
>>>>        ncdf->AOD550_2D  = AOD550_2D
>>>>
>>>>
>>>>       ncdf->a2  = a2(0,:,:,:)
>>>>
>>>>       AOD550_2D!0    = "lat"
>>>>
>>>>       AOD550_2D!1    = "lon"
>>>>
>>>>              AOD550_2D&lat  = a2&XLAT
>>>>
>>>> ===========================================================================================
>>>> here is printVarSummary of "a2"
>>>>
>>>> Variable: a2
>>>>
>>>> Type: float
>>>>
>>>> Total Size: 144434880 bytes
>>>>
>>>>             36108720 values
>>>>
>>>> Number of Dimensions: 4
>>>>
>>>> Dimensions and sizes: [Time | 24] x [bottom_top | 30] x [south_north |
>>>> 229] x [west_east | 219]
>>>>
>>>> Coordinates:
>>>>
>>>>             Time: [   0..  23]
>>>>
>>>> Number Of Attributes: 6
>>>>
>>>>   coordinates : XLONG XLAT XTIME
>>>>
>>>>   stagger :
>>>>
>>>>   units : ?
>>>>
>>>>   description : bin 2 layer optical thickness
>>>>
>>>>   MemoryOrder : XYZ
>>>>
>>>>   FieldType : 104
>>>>
>>>>
>>>>
>>>> On Fri, Nov 10, 2023 at 8:17 PM Dennis Shea <shea at ucar.edu> wrote:
>>>>
>>>>> netCDF operator  'ncks' to extract a variable from a netCDF file and
>>>>> copy it to another
>>>>>
>>>>> %> ncks -v xxx Model.nc XXX.nc
>>>>>
>>>>> where 'xxx' is the name of the variable on the model file
>>>>> ===============================
>>>>>     AOD
>>>>>
>>>>>        *system* <https://www.ncl.ucar.edu/Document/Functions/Built-in/system.shtml>("/bin/rm -f AOD.nc")    ; remove any pre-existing file
>>>>>        ncdf = *addfile* <https://www.ncl.ucar.edu/Document/Functions/Built-in/addfile.shtml>("AOD.nc" ,"c")  ; open output netCDF file
>>>>>
>>>>>     ;===================================================================
>>>>>     ; create global attributes of the file (optional)
>>>>>     ;===================================================================
>>>>>        fAtt               = True            ; assign file attributes
>>>>>        fAtt at title         = "Derived AOD"
>>>>>        fAtt at creation_date = *systemfunc* <https://www.ncl.ucar.edu/Document/Functions/Built-in/systemfunc.shtml> ("date")
>>>>>        *fileattdef* <https://www.ncl.ucar.edu/Document/Functions/Built-in/fileattdef.shtml>( ncdf, fAtt )            ; copy file attributes
>>>>>
>>>>>     ;===================================================================
>>>>>     ; make time an UNLIMITED dimension; recommended  for most applications
>>>>>     ;===================================================================
>>>>>        *filedimdef* <https://www.ncl.ucar.edu/Document/Functions/Built-in/filedimdef.shtml>(ncdf,"time",-1,True)
>>>>>
>>>>>     ;===================================================================
>>>>>     ; output variables directly; NCL will call appropriate functions
>>>>>     ; to write the meta data associated with each variable
>>>>>     ;===================================================================
>>>>>        ncdf->AOD  = AOD
>>>>>
>>>>> ================================
>>>>> See
>>>>> *https://www.ncl.ucar.edu/Applications/method_1.shtml
>>>>> <https://www.ncl.ucar.edu/Applications/method_1.shtml>*
>>>>>
>>>>> On Fri, Nov 10, 2023 at 1:02 AM Setareh Rahimi via ncl-talk <
>>>>> ncl-talk at mailman.ucar.edu> wrote:
>>>>>
>>>>>> Dear all,
>>>>>> I have calculated Aerosol Optical Depth (AOD) from WRF-Chem output
>>>>>> using "TAUAER2" and "TAUAER3" variables (script attached). Instead of using
>>>>>> the created AOD to plot it, I would like to save the AOD as a NetCDF or
>>>>>> tiff file. So how can I do this, please?
>>>>>> I have another question. How can I extract one variable from the
>>>>>> model output and save it as a NetCDF or tiff file?
>>>>>> Please help me with these issues.
>>>>>> Kind regards,
>>>>>>
>>>>>> --
>>>>>> S.Rahimi
>>>>>>
>>>>>> _______________________________________________
>>>>>> ncl-talk mailing list
>>>>>> ncl-talk at mailman.ucar.edu
>>>>>> List instructions, subscriber options, unsubscribe:
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>>>>>>
>>>>>
>>>>
>>>> --
>>>> S.Rahimi
>>>>
>>>>
>>
>> --
>> S.Rahimi
>>
>>

-- 
S.Rahimi
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