  We investigate a lattice of coupled logistic maps where, in addition to the
usual diffusive coupling, an advection term parameterized by an asymmetry in
the coupling is introduced. The advection term induces periodic behavior on a
significant number of non-periodic solutions of the purely diffusive case. Our
results are based on the characteristic exponents for such systems, namely the
mean Lyapunov exponent and the co-moving Lyapunov exponent. In addition, we
study how to deal with more complex phenomena in which the advective velocity
may vary from site to site. In particular, we observe wave-like pulses to
appear and disappear intermittently whenever the advection is spatially
inhomogeneous.
