Edinburgh Napier University

  Over half a century has passed since L. F. Richardson and Henry Stommel conducted their experiment from the pier at Blairmore, Scotland. The relative separations of pairs of immersed floats (made of parsnip) were measured as these became passively transported in the surface waters of Loch Long. In the present note we reopen this investigation with a view to explaining its results in terms of frictional dynamics at the air–sea interface. We suggest how the relative motion of passive tracers can be related to the evolution of impulse generated at the ocean's surface, and indirectly to the self-similarity inherent to this evolution. In particular, an explanation is offered for the dependence of the diffusivity of this process on marker separation.