A solitary wave disturbance of the marine boundary layer over Spencer Gulf revealed by radar observations of migrating insects

During radar observations of a migration of insects across Spencer Gulf, two steadily propagating linear regions of intense radar reflectivity were detected. The passage of these regions, which were moving in a direction almost perpendicular to the general direction of the insect migration, and to the direction of the prevailing wind, was accompanied by a series of large-amplitude wind oscillations. An analysis of the radar and meteorological records indicates that the observed phenomena were manifestations of a solitary buoyancy wave disturbance of the marine boundary layer, and of the interaction of migrating insects with this disturbance. This interpretation suggests that the disturbance was of the same type as those that produce 'Morning Glory' roll clouds and wind gusts in the Gulf of Carpentaria; a similar disturbance is likely 10 have produced a roll cloud reported previously from Spencer Gulf.