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Re: gridtonc for GEM
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- Subject: Re: gridtonc for GEM
- Date: Thu, 2 Oct 2003 09:46:43 -0600 (MDT)
On Thu, 2 Oct 2003, Stuart Wier wrote:
> >To: <address@hidden>
> >cc: "Peter Lewis \(COMET\)" <address@hidden>,
> >cc: "Tim Alberta" <address@hidden>
> >From: "Garry Toth" <address@hidden>
> >Subject: IDV question
> >Organization: UCAR/COMET
> >Keywords: 200310011755.h91HtIk1025833 IDV GEM
>
> Hi,
>
> Unidata currently receives forecast files from the Canadian GEM
> regional
> model from the Canadian Meteorological Centre. Could those data be
> converted into the correct format (netCDF??) to allow them to be
> available
> to the new IDV application? What would be involved in doing this?
> Thanks.
>
> Garry Toth
> COMET
>
Hiya,
Yes Unidata receives the the GEM products and yes they can be converted to
netCDF files correctly. I can't make the statement that they are viewable
with the IDV but Stu will check on it for you. Stu?
To create the GEM netCDF files one needs to use the gribtocdl program to
create the cdl then the gribtonc program create the netCDF file. I
created a GEM.cdl that I'll attach, it should be syntacally correct but
the verbage inside the cdl probably should be corrected. If GEM.cdl works
then forget about using the gribtocdl and just configure pqact.conf for
the gribtonc.
The pqact.conf entry would be something like:
# Canadian GEM data
CMC|EXP
CMC_GEM_reg_.*_.*_([12][0-9][0-9][0-9])([0-1][0-9])([0-3][0-9])([0-2][0-9])_
(.*).grib
PIPE decoders/gribtonc
etc/GEM.cdl
data/GRIB/\1\2\3\4_\5_GEM.nc
The entry wrapped, needs corrected and checked for correct tab insertions.
One can check gribtonc on command line by a similar entry to:
gribtonc -l - GEM.cdl gem.nc < 2003100112_P18.cmcgem
Robb...
===============================================================================
Robb Kambic Unidata Program Center
Software Engineer III Univ. Corp for Atmospheric Research
address@hidden WWW: http://www.unidata.ucar.edu/
===============================================================================netcdf 2003100112_P18.cmcgem{
dimensions:
record = UNLIMITED ; // (reference time, forecast time)
x = 135 ;
y = 94 ;
level = 9 ;
etal = 1 ;
datetime_len = 21 ;
nmodels = 1 ;
ngrids = 1 ;
nav = 1 ;
nav_len = 100 ;
variables:
double reftime(record) ; // reference time of the model
reftime:long_name = "reference time" ;
reftime:units = "hours since 1992-1-1" ;
double valtime(record) ; // forecast time ("valid" time)
valtime:long_name = "valid time" ;
valtime:units = "hours since 1992-1-1" ;
:record = "reftime, valtime" ; // "dimension attribute" -- means
// (reftime, valtime) uniquely
// determine record
char datetime(record, datetime_len) ; // derived from reftime
datetime:long_name = "reference date and time" ;
// units YYYY-MM-DD hh:mm:ssZ (ISO 8601)
float valtime_offset(record) ; // derived as valtime-reftime
valtime_offset:long_name = "hours from reference time" ;
valtime_offset:units = "hours" ;
float level(level) ;
level:long_name = "level" ;
level:units = "hectopascals" ;
float etal(etal) ;
etal:long_name = "ETA level" ;
etal:units = ".0001" ;
long model_id(nmodels) ;
model_id:long_name = "generating process ID number" ;
// navigation variables all use nav dimension
char nav_model(nav, nav_len) ; // navigation parameterization
nav_model:long_name = "navigation model name" ;
int grid_type_code(nav) ;
grid_type_code:long_name = "GRIB-1 GDS data representation type"
;
char grid_type(nav, nav_len) ;
grid_type:long_name = "GRIB-1 grid type" ;
char grid_name(nav, nav_len) ;
grid_name:long_name = "grid name" ;
int grid_center(nav) ;
grid_center:long_name = "GRIB-1 originating center ID" ;
int grid_number(nav, ngrids) ;
grid_number:long_name = "GRIB-1 catalogued grid numbers" ;
grid_number:_FillValue = -9999 ;
char x_dim(nav, nav_len) ;
x_dim:long_name = "x dimension name" ;
char y_dim(nav, nav_len) ;
y_dim:long_name = "y dimension name" ;
long Nx(nav) ;
Nx:long_name = "number of points along x-axis" ;
long Ny(nav) ;
Ny:long_name = "number of points along y-axis" ;
float La1(nav) ;
La1:long_name = "latitude of first grid point" ;
La1:units = "degrees_north" ;
float Lo1(nav) ;
Lo1:long_name = "longitude of first grid point" ;
Lo1:units = "degrees_east" ;
float Lov(nav) ;
Lov:long_name = "orientation of the grid" ;
Lov:units = "degrees_east" ;
float Dx(nav) ;
Dx:long_name = "x-direction grid length" ;
Dx:units = "km" ;
float Dy(nav) ;
Dy:long_name = "y-direction grid length" ;
Dy:units = "km" ;
byte ProjFlag(nav) ;
ProjFlag:long_name = "projection center flag" ;
byte ResCompFlag(nav) ;
ResCompFlag:long_name = "resolution and component flags" ;
// end of navigation variables
float T_TD(record,level,y,x) ;
T_TD:long_name = "Dew point depression (or deficit), deg. K" ;
T_TD:units = "degK" ;
T_TD:_FillValue = -9999.f ;
T_TD:navigation = "nav" ;
float T_TD_etal(record,etal,y,x) ;
T_TD_etal:long_name = "Dew point depression (or deficit), deg.
K" ;
T_TD_etal:units = "degK" ;
T_TD_etal:_FillValue = -9999.f ;
T_TD_etal:navigation = "nav" ;
float Z(record,level,y,x) ;
Z:long_name = "Geopotential height, gpm" ;
Z:units = "gp m" ;
Z:_FillValue = -9999.f ;
Z:navigation = "nav" ;
float N_sfc(record,y,x) ;
N_sfc:long_name = "Total cloud cover, %" ;
N_sfc:units = "percent" ;
N_sfc:_FillValue = -9999.f ;
N_sfc:navigation = "nav" ;
float P_sfc(record,y,x) ;
P_sfc:long_name = "Pressure, Pa" ;
P_sfc:units = "Pa" ;
P_sfc:_FillValue = -9999.f ;
P_sfc:navigation = "nav" ;
float P_msl(record,y,x) ;
P_msl:long_name = "Pressure reduced to MSL, Pa" ;
P_msl:units = "Pa" ;
P_msl:_FillValue = -9999.f ;
P_msl:navigation = "nav" ;
float PRECIP(record,y,x) ;
PRECIP:long_name = "Total precipitation, kg/m2" ;
PRECIP:units = "kg/m2" ;
PRECIP:_FillValue = -9999.f ;
PRECIP:navigation = "nav" ;
float precip_rt(record,y,x) ;
precip_rt:long_name = "Precipitation rate, kg/m2/s" ;
precip_rt:units = "kg/(m2 s)" ;
precip_rt:_FillValue = -9999.f ;
precip_rt:navigation = "nav" ;
float T(record,level,y,x) ;
T:long_name = "Temperature, deg. K" ;
T:units = "degK" ;
T:_FillValue = -9999.f ;
T:navigation = "nav" ;
float T_etal(record,etal,y,x) ;
T_etal:long_name = "Temperature, deg. K" ;
T_etal:units = "degK" ;
T_etal:_FillValue = -9999.f ;
T_etal:navigation = "nav" ;
float u(record,level,y,x) ;
u:long_name = "u-component of wind, m/s" ;
u:units = "m/s" ;
u:_FillValue = -9999.f ;
u:navigation = "nav" ;
float u_etal(record,etal,y,x) ;
u_etal:long_name = "u-component of wind, m/s" ;
u_etal:units = "m/s" ;
u_etal:_FillValue = -9999.f ;
u_etal:navigation = "nav" ;
float v(record,level,y,x) ;
v:long_name = "v-component of wind, m/s" ;
v:units = "m/s" ;
v:_FillValue = -9999.f ;
v:navigation = "nav" ;
float v_etal(record,etal,y,x) ;
v_etal:long_name = "v-component of wind, m/s" ;
v_etal:units = "m/s" ;
v_etal:_FillValue = -9999.f ;
v_etal:navigation = "nav" ;
float omega(record,level,y,x) ;
omega:long_name = "Pressure Vertical velocity, Pa/s" ;
omega:units = "Pa/s" ;
omega:_FillValue = -9999.f ;
omega:navigation = "nav" ;
// global attributes
:history = "2003-10-02 09:13:57 - created by gribtocdl 1.4 -
12.12.2002" ;
:title = "2003100112_P18.cmcgem" ;
:Conventions = "NUWG" ;
:version = 0.0 ;
data:
level = 1000.0, 925.0, 850.0, 700.0, 500.0, 400.0, 250.0, 150.0, 100.0 ;
etal = 10000.0 ;
model_id = 36 ;
// Navigation
nav_model = "GRIB1" ;
grid_type_code = 5 ;
grid_type = "Polar stereographic projection" ;
grid_name = " " ;
grid_center = 54 ;
grid_number = 255 ;
x_dim = "x" ;
y_dim = "y" ;
Nx = 135 ;
Ny = 94 ;
La1 = 27.202999 ;
Lo1 = -135.212997 ;
Lov = 249.000000 ;
Dx = 60000.000000 ;
Dy = 60000.000000 ;
// Pole in proj. plane = North ;
ProjFlag = 0 ;
ResCompFlag = 136 ;
}
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