[ncl-talk] sub: Regridding NARR data

[dale zuri]

Hi NCL user,
I would like to regrid the curvilinear grid to lat/lon gaussion grid.  I
would appreciate any help to fix this.

Thanks

My modifications in the above program to reflect that:
 lat  = latGau(nlat, "lat", "latitude", "degrees_north")

Opt at DstGridType    = "gaussian"

Destination grid file information:

wget
ftp://nomads.ncdc.noaa.gov/modeldata/cfsv2_forecast_6-hourly_9mon_flxf/2012/201201/20120102/2012010200/flxf2012010206.01.2012010200.grb2
Warning message:

fatal:Variable (latlon_dims) is undefined

fatal:["Execute.c":8637]:Execute: Error occurred at or near line 3754 in
file /Users/akila/ncl-6.6.2/lib/ncarg/nclscripts/esmf/ESMF_regridding.ncl


fatal:["Execute.c":8637]:Execute: Error occurred at or near line 3866 in
file /Users/akila/ncl-6.6.2/lib/ncarg/nclscripts/esmf/ESMF_regridding.ncl


fatal:["Execute.c":8637]:Execute: Error occurred at or near line 4019 in
file /Users/akila/ncl-6.6.2/lib/ncarg/nclscripts/esmf/ESMF_regridding.ncl


fatal:["Execute.c":8637]:Execute: Error occurred at or near line 132 in
file dale_SourceRegrid.ncl


fatal:Variable (prcJJA_regrid) is undefined

fatal:["Execute.c":8637]:Execute: Error occurred at or near line 133 in
file dale_SourceRegrid.ncl


fatal:Variable (prcJJA_regrid) is undefined

fatal:["Execute.c":8637]:Execute: Error occurred at or near line 134 in
file dale_SourceRegrid.ncl


(0) -------------------

fatal:Undefined identifier: (prcJJA_regrid) is undefined, can't continue

fatal:["Execute.c":8637]:Execute: Error occurred at or near line 181 in
file dale_SourceRegrid.ncl

On Mon, Mar 2, 2020 at 6:47 AM Dennis Shea <shea at ucar.edu> wrote:

> I did not look closely at what I had done. I made a graphical mistake.
> The attached is correct.
>
> On Sun, Mar 1, 2020 at 8:25 PM Dennis Shea <shea at ucar.edu> wrote:
>
>> The following ESMF example illustrates how to interpolate from a NARR
>> grid to a rectilinear grid:
>> *http://www.ncl.ucar.edu/Applications/ESMF.shtml*
>> <http://www.ncl.ucar.edu/Applications/ESMF.shtml>
>> ESMF_wgts_30.ncl
>> ------------------------
>> The ESMF software does NOT work with cartesian [projection] coordinates ['
>> *x'* , '*y*'] which have units of meters.
>>                     ; the following are not correct
>>
>>   lon2d    = f1[:]->x
>>
>>   lat2d    = f1[:]->y
>>
>>
>> The ESMF software works with latitudes and longitudes.
>>
>> You should extract the latitudes and longitudes from the first file only:
>>
>>
>>   lon2d = f1*[0]*->lon             ; read NARR longitude from 1st file
>>   lat2d = f1*[0]*->lat             ; read NARR latitude
>>
>> -----------------
>>
>>
>> See attached. It is a combination of your script and ESMF_wgts_30.ncl
>>
>>
>>
>> On Sat, Feb 29, 2020 at 2:56 PM dale zuri via ncl-talk <ncl-talk at ucar.edu>
>> wrote:
>>
>>> Hi NCL user,
>>> I have been trying to regrid NARR 0.3 resolution to 190x384 using the
>>> ESMF regrid function. The regrid was successful, however the output values
>>> seem unrealistic and not correct.
>>> I would appreciate any suggestion to fix the problem.
>>> Thanks
>>>
>>> Here the code:
>>>  diri1 = "/NARR/daily/prate/"
>>>
>>> fill1 = systemfunc("for((i="+yrstrt+";i<="+yrend+";i+=1)); do ls "+
>>> diri1 +"*$i*; done")
>>>
>>> print(fill1)
>>>
>>> f1    = addfiles (fill1, "r")   ; note the "s" of addfile
>>>
>>> ListSetType (f1, "cat")
>>>
>>> uT1    = f1[:]->prate             ; read T from all files
>>>
>>> lon2d    = f1[:]->x             ; read T from all files
>>>
>>> lat2d    = f1[:]->y             ; read T from all files
>>>
>>> printVarSummary (uT1)
>>>
>>>   uT1 at _FillValue = uT1 at missing_value  ; fix missing value
>>>
>>> printMinMax(uT1,0)
>>>
>>>   uT  = short2flt( uT1 )   ; apply scale and offset attributes
>>>
>>> xMon = calculate_monthly_values (uT, "avg", 0,True)
>>>
>>> printVarSummary(xMon)
>>>
>>> printMinMax(xMon,0)
>>>
>>> T1 = month_to_season (xMon, "JJA")
>>>
>>> printVarSummary(T1)
>>>
>>> T1=T1*86400*92
>>>
>>> printMinMax(T1,0)
>>>
>>> ;-- define the T255 grid (lat x lon - 256x512)
>>>
>>> nlat = 190 ;-- number of latitudes
>>>
>>> nlon = 384 ;-- number of longitudes
>>>
>>> grint = 0.9375 ;-- grid spacing
>>>
>>> dst_lat = fspan((-90.0+grint),(90.-grint),nlat)*1d ;-- type double
>>>
>>> dst_lat!0 = "lat" ;-- dimension name
>>>
>>> dst_lat at units = "degrees_north" ;-- dimension units
>>>
>>> dst_lon = fspan(0.0,(360.-grint),nlon)*1d ;-- type double
>>>
>>> dst_lon!0 = "lon" ;-- dimension name
>>>
>>> dst_lon at units = "degrees_east" ;-- dimension units
>>>
>>> ;-- set ESMF resources
>>>
>>> Opt = True
>>>
>>> Opt at InterpMethod = "patch" ;-- interpolation method
>>>
>>> Opt at SrcFileName = "ECHAM5_SCRIP_bilinear.nc" ;-- new source file name
>>>
>>> Opt at WgtFileName = "ECHAM5toWorldCurvilinear_bilinear.nc";-- weights file
>>>
>>> Opt at ForceOverwrite = True ;-- force overwrite
>>>
>>>  Opt at DstFileName = "WorldRectilinear_SCRIP_bilinear.nc";-- destination
>>> file
>>>
>>> Opt at DstGridType = "rectilinear" ;-- Destination grid
>>>
>>> Opt at DstGridLon = dst_lon
>>>
>>> Opt at DstGridLat = dst_lat
>>>
>>> newgrid = ESMF_regrid(T1,Opt)
>>>
>>> ;newgrid  = f2fsh_Wrap(T1,(/190,384/))
>>>
>>> printVarSummary (newgrid)
>>>
>>> printMinMax(newgrid,0)
>>>
>>>
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>>
>>
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