Hello,
I am trying to modify some NCL code I saw (thanks Ryan/Dennis) in the
ncl-talk archives. It was originally written to convert 3d
(time,lat,lon) ECMWF output to netCDF.
As a first cut, since my RUC grib files each represent a single forecast
hour, I have commented out the time references. By using the Navy's
"gribsimp" and NCL print(filename), I have found it is a 151x113 grid.
gribsimp also shows the latitude of the first grid point and the
longitude of the first grid point.
Right now it is complaining:
"fatal:Number of dimensions in parameter (2) of (filedimdef) is (2), (1)
dimensions were expected
fatal:Execute: Error occurred at or near line 110"
parameter(2) is dimNames which = (/"lat","lon"/).
I don't follow why it is expecting 1 dimension with the dimNames
parameter in the filedimdef call??
At the very bottom is a NCL print of the GRIB file to provide info on
the grid size and the lat and lon variables.
Thanks for any advice.
--Steve Kirby
Research Meteorologist
Here is the NCL code:
;***************************************************
; RUC full variable conversion to netcdf
;***************************************************
load "/home/skirby/NCL/lib/ncarg/nclscripts/csm/contributed.ncl"
;;function rdVar3D (f:file, vName:string, time:integer)
function rdVar2D (f:file, vName:string)
begin
var = f->$vName$ ; read variable
printVarSummary(var)
;; var!0 = "time" ; assign 'conventional' dimension names
;; var!1 = "lat"
var!0 = "lat"
;; var!2 = "lon"
var!1 = "lon"
; following not needed for current application
;var&time = time ; assign integer time coord variable
return(var)
end
begin
;***************************************************
; get all file names; then loop over each file
;***************************************************
; diri = "./surface_state_4xdaily/" ; input directory
diri = "/home/skirby/TEMP/" ; input directory
; fils = systemfunc("cd "+diri+"; ls e4oper.an.sfc.200*")
fils = systemfunc("cd "+diri+"; ls ruc*grb")
nfils = dimsizes(fils)
print (fils)
OS = systemfunc ("uname")
diro = "./"
;***************************************************
; specify desired GRIB variables
;***************************************************
;system("banner HI")
do nf=0,nfils-1
print ("===========> nf="+nf+" <========================")
wcStrt = systemfunc("date") ; wall clock start
;***************************************************
; open grib file and get variable names
;***************************************************
grib_in = addfile(diri+fils(nf)+".grb","r")
names = getfilevarnames(grib_in) ; get ALL variable names
wallClockElapseTime(wcStrt, "Read/open file file: "+fils(nf), 0)
ncl_names = names
; lat = grib_in->g4_lat_1 ; latitude
lat = grib_in->gridlat_236 ; latitude
lat!0 = "lat" ; rename NCL's GRIB dimension names
; lon = grib_in->g4_lon_2 ; longitude
lon = grib_in->gridlon_236 ; longitude
lon!0 = "lon" ; to 'conventional' dimension
;; stime = grib_in->initial_time0
;; stime = grib_in->initial_time
;; time = grib_stime2itime (stime) ; string to integer
(contributed.ncl)
if (nf.eq.0) then
print (names)
;; print (stime+" "+time)
end if
;; ntim = dimsizes(time)
nlat = dimsizes(lat)
mlon = dimsizes(lon)
;***************************************************
; open output netcdf file
; create parameters and output file
;***********************************************
system ("rm -f "+diro+fils(nf)+".nc") ; remove pre-existing file
(if any)
netcdf_out = addfile(diro+fils(nf)+".nc","c") ; "c"reate the
netCDF file
;***********************************************
;***********************************************
; assign file attributes
;***********************************************
fAtt = True
fAtt@title <mailto:fAtt@title> = "GRIB-to-netCDF: processed by
sfkirby@arl.army.mil <mailto:sfkirby@arl.army.mil> "
fAtt@source_file <mailto:fAtt@source_file> = fils(nf)
fAtt@Conventions <mailto:fAtt@Conventions> = "None"
fAtt@System <mailto:fAtt@System> = OS
fAtt@creation_date <mailto:fAtt@creation_date> = systemfunc
("date")
fileattdef( netcdf_out, fAtt )
;***********************************************
; predefine coordinate information
;***********************************************
;; dimNames = (/"time", "lat", "lon" /)
dimNames = (/"lat","lon" /)
;; dimSizes = (/ ntim , nlat, mlon/)
dimSizes = (/ nlat, mlon/)
;; dimUnlim = (/ True , False, False/)
dimUnlim = (/ False,False/)
filedimdef(netcdf_out, dimNames , dimSizes, dimUnlim )
;; filevardef (netcdf_out, "time" , typeof(time), "time" )
;; filevarattdef(netcdf_out, "time", time)
filevardef (netcdf_out, "lat", typeof(lat), "lat")
filevarattdef(netcdf_out, "lat", lat)
filevardef (netcdf_out, "lon", typeof(lon), "lon")
filevarattdef(netcdf_out, "lon", lon)
;***********************************************
; predefine variable sizes
; (unfortunately) must read variables from GRIB file
; needed for filevarattdef
;***********************************************
do i=3, dimsizes(ncl_names)-1 ;;sk -- why 3?
;; TMP = rdVar3D (grib_in, names(i) ,time)
TMP = rdVar2D (grib_in, names(i))
;; filevardef(netcdf_out, names(i) \
;; , typeof(TMP), (/"time","lat","lon"/) )
filevardef(netcdf_out, names(i) \
, typeof(TMP), (/"lat","lon"/) )
filevarattdef(netcdf_out, names(i) , TMP)
end do
wallClockElapseTime(wcStrt, "Defintion phase took ", 0)
;***************************************************
; write data values to predefined locations
;***************************************************
wcStrt = systemfunc("date") ; wall clock start
;; netcdf_out->time = (/ time /)
netcdf_out->lat = (/ lat /)
netcdf_out->lon = (/ lon /)
do i=3, dimsizes(names)-1
;; TMP = rdVar3D (grib_in, names(i) ,time)
TMP = rdVar2D (grib_in, names(i))
netcdf_out->$names(i)$ = (/ TMP /)
end do
wallClockElapseTime(wcStrt, "Write phase took ", 0)
;; delete (stime) ; may change next "nf" iteration
;; delete (time)
delete (names)
delete (lat)
delete (lon)
delete (TMP)
end do
end
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++
For reference, below is a NCL dump of the RUC grib file dimensions and
some variables , PRES_236_SFC,gridlat_236 and gridlon_236:
filename: ruc
path: ruc.grb
file global attributes:
dimensions:
gridx_236 = 113
gridy_236 = 151
lv_ISBL2 = 37
lv_SPDY3 = 6
variables:
float PRES_236_SFC ( gridx_236, gridy_236 )
center : US National Weather Service - NCEP (WMC)
long_name : Pressure
units : Pa
_FillValue : -999
coordinates : gridlat_236 gridlon_236
level_indicator : 1
grid_number : 236
parameter_number : 1
model : RUC Model from FSL (isentropic; scale: 20km at
40N)
forecast_time : 1
initial_time : 06/14/2005 (00:00)
float gridlat_236 ( gridx_236, gridy_236 )
corners : <ARRAY>
GridType : Lambert Conformal Secant or Tangent, Conical or
bipolar
units : degrees_north
Latin2 : 25
Latin1 : 25
Dy : 40635
Dx : 40635
Lov : 265
Lo1 : 233.862
La1 : 16.281
float gridlon_236 ( gridx_236, gridy_236 )
corners : <ARRAY>
GridType : Lambert Conformal Secant or Tangent, Conical or
bipolar
units : degrees_east
Latin2 : 25
Latin1 : 25
Dy : 40635
Dx : 40635
Lov : 265
Lo1 : 233.862
La1 : 16.281
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++
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