processing grib files

hi all,

i've run into a problem trying to subset and convert some grib files to
netcdf and need some help.

in process i'm doing some unit conversions and the resulting datasets are
missing attributes. i've tried to follow examples for creating and defining
a netcdf file as closely as possible, but it seems i'm not doing something
correctly here.

the current error is complaining that the array sizes aren't the same,
which they aren't:
"fatal:_NclBuildArray: each element of a literal array must have the same
dimension sizes, at least one item doesn't"

i've searched the archives, but haven't been able to get a good grasp on
how people solved this problem. what's the proper way to do this?

thanks in advance for your help,
john

;**************************************************
; loops through the directory and converts each
; file to .nc. variables are converted to correct
; UEB units.
;**************************************************
begin
ncfiles=systemfunc("ls *.nc")
if(dimsizes(ncfiles) .gt. 0) then
  system("rm *.nc") ;remove any pre-existing file
end if

;specify extent
latN=42.852 ;latN=42.851414
latS=40.500 ;latS=40.581516
lonL=-112.620 ;lonL=-112.561063
lonR=-110.480 ;lonR=-110.598790

cmd="ls *.grb"
grbFiles=systemfunc(cmd)
nfiles=dimsizes(grbFiles)

; loop through the files and process
do n = 0, nfiles-1
  g=addfile(grbFiles(n),"r")
  ;print(g)
  fn=str_split(grbFiles(n),".")
  outfn=fn(0)+"."+fn(1)+"."+fn(2)+"."+fn(3)+".nc"
  ;print(outfn)

;define the output file
  ncdf_out = addfile("./"+outfn ,"c") ; create output netCDF file
setfileoption(ncdf_out,"DefineMode",True)
 ;setup variable atts
varsize=new((/19,17/),float,"No_FillValue")
latsize=new((/19/),float,"No_FillValue")
lonsize=new((/17/),float,"No_FillValue")

;assign file attributes
fAtt = True
fAtt@title = "NLDAS Data - converting .grb to .nc"
fAtt@source_file = grbFiles(n)
fAtt@Conventions = "None"
fAtt@creation_date = systemfunc ("date")
fileattdef(ncdf_out, fAtt )

;setup variable dimensions
        dimNames = (/"lat_110","lon_110","TEMP"/)
dimSizes = (/dimsizes(latsize),dimsizes(lonsize),dimsizes(varsize) /)
dimUnlim = (/False, False, False/)
filedimdef(ncdf_out,dimNames,dimSizes,dimUnlim)
    ; predefine names, type, dimensions
    filevardef(ncdf_out,"lat_110",typeof(latsize),getvardims(latsize))
    filevardef(ncdf_out,"lon_110",typeof(lonsize),getvardims(lonsize))
    filevardef(ncdf_out,"TEMP",typeof(varsize),getvardims(varsize))

    ; predefine each variable's attributes
    filevarattdef(ncdf_out,"lat_110" ,g->$"lat_110"$({latS:latN}))
    filevarattdef(ncdf_out,"lon_110",g->$"lon_110"$({lonL:llonR}))

filevarattdef(ncdf_out,"TEMP",g->$"TMP_110_HTGL"$({latS:latN},{lonL:lonR}))
    ;setfileoption(ncdf_out,"DefineMode",False) ; optional

;do the conversions and add to ncdf_out
  tempc=g->$"TMP_110_HTGL"$({latS:latN},{lonL:lonR})-273.15
    ncdf_out->tempc = (/TEMP/)

;ncdf_out->$"PRECIP"$=g->A_PCP_110_SFC_acc1h({latS:latN},{lonL:lonR})*0.001
  ;ncdf_out->$"SW"$=g->DSWRF_110_SFC({latS:latN},{lonL:lonR})*(1.0/3.6)
  ;ncdf_out->$"LW"$=g->DLWRF_110_SFC({latS:latN},{lonL:lonR})*(1.0/3.6)

  ;u=g->U_GRD_110_HTGL({latS:latN},{lonL:lonR})
;v=g->V_GRD_110_HTGL({latS:latN},{lonL:lonR})
;ncdf_out->$"WIND"$=sqrt((u*u)+(v*v))

  ;press=g->PRES_110_SFC({latS:latN},{lonL:lonR})
;ncdf_out->$"PRESS"$=press

;spfh=g->SPF_H_110_HTGL({latS:latN},{lonL:lonR})
;ncdf_out->$"SPFH"$=spfh

  ;esat=611.0*exp((17.3*tempc)/(237.3+tempc))
  ;ncdf_out->$"RH"$=(press*spfh)*(esat*(spfh+0.622))

; print(ncdf_out)

end do
end

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Received on Fri Feb 21 10:24:52 2014