An unusual atmospheric vortex street

Abstract

Atmospheric vortex streets quite often form in the wake of tall islands in the marine atmospheric boundary layer. Most satellite pictures of this phenomenon show that two rows of staggered, counter-rotating vortices are aligned more or less in a straight line downstream of the islands, like Karman vortex streets behind cylindrical obstacles. In this paper however, an unusual downstream behaviour of an atmospheric vortex street in the wake of Heard Island is discussed, where there is a sudden change in orientation of the vortices downwind of the island. The reason for this development can be traced to a special synoptic weather situation.