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)
              (defined in gcm_vert_diff_down -- not used elsewhere)

     dflux_t = derivative of the temperature flux at the top of the lowest
               atmospheric layer with respect to the temperature
               of that layer  (J/(m2 K))
               (defined in gcm_vert_diff_d