20020219: Plotting two differnt PARM at two diff. times

>From: "Siffert, Andy" <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200202192141.g1JLfjx00339

>
>
>Hello,
>I'm trying to figure out how to plot the difference between two different
>PARM at two different times on to one plot. In this case I have created and
>.gem file with AVEEU which is the Avg. of the ECMWF from the given times.
>AVEMRF is the Avg. of the MRF from the given times.
>
>
>GEMPAK-GDINFO>:
>NUM       TIME1              TIME2           LEVL1 LEVL2  VCORD PARM
>2     020218/1200F156   020218/1200F240      850         PRES AVEEU
>13     020219/0000F144   020219/0000F228      850         PRES AVEMRF
>
>I'm not sure how and what I can use to plot the differences between the two
>PARM.
>
>gdplot will not work because I have two different times.
>
>that or I'm not specifying my 
>gddattim and gfunc properly.
>
>Any idea's would be greatly appreciated.
>
>Thanks,
>Andy 
>

Andy,

Use an any gempak program (including gdplot):

GVCORD=PRES
GLEVEL=850
GDATTIM=020218/1200F156:020218/1200F240
GFUNC=sub(AVEEU,AVEMRF^020219/0000F144:020219/0000F228)

You can override time, vertical coordinate and level for any 
paremeter using the ^, @, and % parameters as specified in
the "phelp gparm" help.

Also, review the tutorial:
http://www.unidata.ucar.edu/packages/gempak/tutorial/diagnostics.html

Steve Chiswell