[gradsusr] Incorrect Winds from NCEP NAM file

Donald Van Dyke Don.VanDyke at noaa.gov
Thu Oct 27 18:33:24 EDT 2011


Hello,

I'm not sure if this is a grib2 file problem or a GrADS problem, but if 
I try to plot the winds from the attached NAM grib2 file from NCEP, the 
wind is plotted incorrectly.  I am using g2ctl.pl with no flags and 
gribmap -i to create the .ctl and .idx files.  In the GrADS script, I am 
using simple commands such as

"set lev 250"
"d mag(ugrdprs,vgrdprs)*1.943844449"
"d skip(ugrdprs*1.943844449,2,2);skip(vgrdprs*1.943844449,2,2)"

The image created is attached along with an image from NCEP showing what 
the winds should have looked like over my area in the Florida 
Panhandle.  They're obviously not northerly.  I am currently using 
grads.2.0.a9.  I have also attached the grib2 file as well as the .ctl 
file and .idx file I created with g2ctl.pl and gribmap.  Thanks.

-Don



-------------- next part --------------
A non-text attachment was scrubbed...
Name: nam_namer_000_250_wnd_ht.gif
Type: image/gif
Size: 74769 bytes
Desc: not available
Url : http://gradsusr.org/pipermail/gradsusr/attachments/20111027/0fc1bd84/attachment-0003.gif 
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: 0.ctl
Url: http://gradsusr.org/pipermail/gradsusr/attachments/20111027/0fc1bd84/attachment-0003.pl 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: nam.t00z.awip3200.tm00.grib2
Type: application/octet-stream
Size: 101281 bytes
Desc: not available
Url : http://gradsusr.org/pipermail/gradsusr/attachments/20111027/0fc1bd84/attachment-0006.obj 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: nam.t00z.awip3200.tm00.grib2.idx
Type: application/octet-stream
Size: 45480 bytes
Desc: not available
Url : http://gradsusr.org/pipermail/gradsusr/attachments/20111027/0fc1bd84/attachment-0007.obj 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: nam250wind-0.png
Type: image/png
Size: 38534 bytes
Desc: not available
Url : http://gradsusr.org/pipermail/gradsusr/attachments/20111027/0fc1bd84/attachment-0003.png 


More information about the gradsusr mailing list