  Generalized action invariants are identified for various models of drift wave
turbulence in the presence of the mean shear flow. It is shown that the wave
kinetic equation describing the interaction of the small scale turbulence and
large scale shear flow can be naturally written in terms of these invariants.
Unlike the wave energy, which is conserved as a sum of small- and large- scale
components, the generalized action invariant is shown to correspond to a
quantity which is conserved for the small scale component alone. This invariant
can be used to construct canonical variables leading to a different definition
of the wave action (as compared to the case without shear flow). It is
suggested that these new canonical action variables form a natural basis for
the description of the drift wave turbulence with a mean shear flow.
