We study the initial instability of flat sand surface and further nonlinear
dynamics of wind ripples. The proposed continuous model of ripple formatio
n allowed us to simulate the development of a typical asymmetric ripple sha
pe and the evolution of a sand ripple pattern. We suggest that this evoluti
on occurs via ripple merger preceded by several solitonlike interaction of
ripples. [S1063-651X(99)04507-9].