[Wrf-users] NAM 12-km Tiled data for WRF Initialization

Feng Liu FLiu at azmag.gov
Thu Feb 10 11:44:05 MST 2011

There are two resources you can download the datasets from 12-km NAM model

(1)    http://nomads.ncdc.noaa.gov/data.php#hires_weather_datasets, you may have a direct access to this site.

(2)    http://dss.ucar.edu/datasets/ds335.0/matrix.html you may need to register before you get access. That is free.

The grid value is 218 (B). You should build your WPS with GRB2 option because 12-km NAM are GRIB2 data. You may check out the basic grid information about the datasets as below before you download them. In respect to application of WPS with multiple tiles in a data, please refer to 3-34~ 37 in the latest version of User's Guide issued in July 2010. I hope it is helpful.

218 (B)[B]   Grid over the Contiguous United States (used by the 12-km NAM Model) (Lambert Confo
Nx 614
Ny 428
La1 12.190N
Lo1 226.514E = 133.459W
Res. & Comp. Flag 0 0 0 0 1 0 0 0
Lov 265.000E = 95.000W
Dx 12.19058 km
Dy 12.19058 km
Projection Flag (bit 1) 0 (not bipolar)
Scanning Mode (bits 1 2 3) 0 1 0
Lat/Lon values of the corners of the grid
(1,1) 12.190N, 133.459W
(1,428) 54.564N, 152.878W
(614,428) 57.328N, 49.420W
(614,1) 14.342N, 65.127W
Pole point
(I,J) (347.668, 1190.097)

Good luck.

From: wrf-users-bounces at ucar.edu [mailto:wrf-users-bounces at ucar.edu] On Behalf Of Wu, Zhong-Xiang (Lowell,MA-US)
Sent: Wednesday, February 09, 2011 12:01 PM
To: wrf-users at ucar.edu
Subject: [Wrf-users] NAM 12-km Tiled data for WRF Initialization


I am trying to use NAM 12-km tiled forecasts from NCEP in the WPS processing to create met initial files for WRF modeling.  My WRF domain covers an area more than one NAM 12-km tile, so multiple NAM files are needed at one hour.

Is there anyone who used the NAM 12-km tiled forecasts to initialize WRF in the similar way? And how should I use the data if WPS accepts multiple tiled files?



Zhong-Xiang Wu, Ph.D
650 Suffolk Street
Lowell, Massachusetts, 01854

Email: zwu at trcsolutions.com<mailto:zwu at trcsolutions.com>
          zhong at alum.mit.edu<mailto:zhong at alum.mit.edu>
Tel:     978-656-3667
 Fax:   978-453-1995
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