20050804: hrly strm

>From: "Patrick L. Francis" <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200508041448.j74Emajo024772

>
>I would be grateful for an example / 
>guidance on how to create hourly surface
>streamlines with surface obs.
>
>

Patrick,

Create a grid file using GDCFIL. You can either specify your own
grid spacing/avigation, or copy one using CPYFIL. For example:

 GDOUTF   = sfc.gem
 PROJ     =  
 GRDAREA  =  
 KXKY     =  
 MAXGRD   = 2000
 CPYFIL   = #212
 ANLYSS   =  
 GEMPAK-GDCFIL>

Then after creating your surface grid file, run OABSFC on your surface data
(eg metars) to grid the u and v wind components:

 SFFILE   = metar
 GDFILE   = sfc.gem
 SFPARM   = uwnd;vwnd
 DATTIM   = 1800
 DTAAREA  =  
 GUESS    =  
 GUESFUN  =  
 GAMMA    = 0.3
 SEARCH   = 20
 NPASS    = 2
 QCNTL    =  
 OABND    =  
 GEMPAK-OABSFC>

The use GDPLOT2 to display the streamline field:

 GDFILE   = sfc.gem
 GDATTIM  = 1800
 GLEVEL   = 0
 GVCORD   = none
 SCALE    = 0
 GDPFUN   = wnd
 TYPE     = s
etc.

Lastly, plot your metar observations with SFMAP:

 SFPARM   = metar
 DATTIM   = 1800
 SFFILE   = metar
 COLORS   =  
 CLEAR    = n
 FILTER   = YES
etc.


Steve Chiswell
Unidata User Support
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