Vortex cloud street during AMTEX 75

Strong northerly flow across Cheju Island, Korea, during the 1975 Air Mass Transformation Experiment (AMTEX 75) resulted in a pronounced vortex cloud street to the lee of the island on February 17 1975. This pattern has been studied and explained in terms of classical von Kármán eddies shed in laminar free flow moving past a cylindrical obstacle under subcritical Reynolds number conditions.

DMSP satellite imagery and AMTEX aerological data have given the shedding frequency of the vortices that are contained in the mixed boundary layer below the capping inversion to be one per 3 h. The island extends to nearly 2 km above sea level and penetrates the base of the inversion layer at a height of approximately 600 m. At this height the island diameter is about 20 km, a figure in good agreement with the independently inferred vortex shedding diameter.