  We present a simple one-dimensional model to describe the evolution of a
transverse dune field. The model is characterized by the distances between the
dunes and their heights, which determine the inter-dune sand flux. The model
reproduces the observation that the dunes in a given field have approximately
all the same height. We find that this result is independent of the initial
configuration of the field, as well as of coalescence effects between migrating
dunes. The time for the final state to be reached is studied as a function of
the relevant phenomenological parameters.
