A summary of four, five-day clear air turbulence reporting periods

This paper summarises the results of the four ICAO five-day clear air turbulence (CAT)reporting periods covering the South Pacific region and conducted on selected days in December 1964 and March, June and September, 1965. The incidence of CAT was greatest in March (autumn). Much of this CAT occurred over mountains. Vertical wind shear, either averaged over a 10,000 ft layer above and a 10,000 ft layer below the jet stream, or in the 10,000 ft layer below the jet stream, was the most successful parameter.