[gradsusr] data not in GRIB format

[Huddleston, John]

Hao

CMAQ files usually are ioapi or WRF compliant. If they are ioapi, run the 'ncdump -h file.ncf > h' and look at the global characteristics.  It will have everything you need to compose the control file.

If they are WRF compliant, you will have to go back to the modeler who created them.

Please see http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html#GRID138 as an example of the information you need.

John Huddleston, PhD

From: gradsusr-bounces at gradsusr.org [mailto:gradsusr-bounces at gradsusr.org] On Behalf Of Hao He
Sent: Thursday, May 06, 2010 12:15 PM
To: GrADS Users Forum
Subject: Re: [gradsusr] data not in GRIB format

John,
   I start to work on the .ctl file, and I have a question about the xdef and ydef. As you plotted, the left corner is not the minimal longitude and latitude of the domain. Which value should I use?

Best

Hao
On Wed, May 5, 2010 at 2:16 PM, Huddleston, John <Huddleston at cira.colostate.edu<mailto:Huddleston at cira.colostate.edu>> wrote:
Hao, this might be closer if it is 30KM. Change the ytime and year accordingly. John

dset ^YourFile.ncf
dtype netcdf
title Vertically integrated atmos chem/aerosol vbles
pdef 94 67 lcc 24.87 -127.10 1 1 33 45 -114.00 30000 30000
undef -9999
xdef 94 linear -131.336    0.48
ydef 67 linear  24.87      0.300

zdef 1 linear 1 1
tdef 24  linear 00:00Z20apr2006 1hr

vars 8
NO2=>no2  1 t,z,y,x NO2
NO=>no  1 t,z,y,x NO
O=>o  1 t,z,y,x O
O3=>o3  1 t,z,y,x O3
NO3=>no3  1 t,z,y,x NO3
CO=>co  1 t,z,y,x CO
CXO3=>cxo3  1 t,z,y,x cxo3
NH3=>nh3  1 t,z,y,x NH3
endvars

________________________________
From: gradsusr-bounces at gradsusr.org<mailto:gradsusr-bounces at gradsusr.org> [gradsusr-bounces at gradsusr.org<mailto:gradsusr-bounces at gradsusr.org>] On Behalf Of Hao He [haohe.umcp at gmail.com<mailto:haohe.umcp at gmail.com>]
Sent: Wednesday, May 05, 2010 11:59 AM
To: GrADS Users Forum
Subject: Re: [gradsusr] data not in GRIB format
That is great! My grid size is 30 km instead of 36 km, and I think the difference is trivial. I will read the format and modified it to my own grid.
Thanks a lot!

Hao
On Wed, May 5, 2010 at 1:52 PM, Huddleston, John <Huddleston at cira.colostate.edu<mailto:Huddleston at cira.colostate.edu>> wrote:
Hao

If it is 36 kilometer CMAQ netCDF you can probably start with this grid control definition.

dset ^YourFile.ncf
dtype netcdf
title Vertically integrated atmos chem/aerosol vbles
pdef 148 112 lcc 16.77 -121.51 1 1 33 45 -97.00 36000 36000
undef -9999
xdef 148 linear -139.285    0.57565
ydef 112 linear  16.77      0.3600
zdef 1 linear 1 1
tdef 72  linear 00:00Z20apr2006 1hr
vars 8
NO2=>no2  1 t,z,y,x NO2
NO=>no  1 t,z,y,x NO
O=>o  1 t,z,y,x O
O3=>o3  1 t,z,y,x O3
NO3=>no3  1 t,z,y,x NO3
CO=>co  1 t,z,y,x CO
CXO3=>cxo3  1 t,z,y,x cxo3
NH3=>nh3  1 t,z,y,x NH3
endvars

john Huddleston, PhD, PE
________________________________
From: gradsusr-bounces at gradsusr.org<mailto:gradsusr-bounces at gradsusr.org> [gradsusr-bounces at gradsusr.org<mailto:gradsusr-bounces at gradsusr.org>] On Behalf Of Hao He [haohe.umcp at gmail.com<mailto:haohe.umcp at gmail.com>]
Sent: Tuesday, May 04, 2010 1:58 PM
To: gradsusr at gradsusr.org<mailto:gradsusr at gradsusr.org>
Subject: [gradsusr] data not in GRIB format
Hi,
   I have a 2D data set with uneven Lon and Lat distribution. I notice that the GRIB data for GrADS has even grids, so I am wondering whether it is possible to display this data set on GrADS? Thanks for help!

Hao

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