vertical integrated moisture convergence by MM5 model output

[Satyaban BishoyiRatna]

Dear Grads-user,
     I am trying to calculate vertical integrated moisture convergence from our MM5 model output.I have written a script for it.But it is not working.I am getting the picture but it is not the right one.
   
'open domain3.ctl'
'set map 1 1 9'
'set gxout shaded'
'set t 25'
'define qu=q*u'
'define qv=q*v'
'define qq = -hdivg(qu,qv)'
'd vint(prs(z=3)/100.,qq,200)'
     Please suggest me to calculate this correctly. I have pressure level MM5 model output with following variables.

    ps 0 99 pstar (Pa)
    pslv 0 99 sea level prs (mb)
    u 20 99 u wind (m/s)
    v 20 99 v wind (m/s)
    q 20 99 mixing ratio (kg/kg)
    z 20 99 height AGL (m)
    td 20 99 dewpoint temp (C)
    rh 20 99 rel humidity (%)
    prs 20 99 pressure (Pa)
    
I am also in doubt which of the above pressure  variable should use to calculate moisture convergence.
    Thanking you.

Regards
Satyaban
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