                 dflux_q,   & 
                                   delta_t,   &
                                   delta_q
 


        for full description of these fields, and the rationale for 
              saving these particular fields, 
                 see  <A HREF="vert_diff.tech.ps">vert_diff.tech.ps</A>

     dtmass = dt/mass, where dt = atmospheric time step (sec)
              ((i+1)-(i-1), not (i+1)-i, if atmos model is leapfrog)
              mass = mass of lowest atmospheric layer (Kg/m2)
    