Abstract
Abstract Following a suggestion by Deardorff, Hess et al. have proposed that a necessary condition for the formation of dust devils is −h/L⩾50, where h is the convective boundary layer height and L the Obukhov length. A survey of pilots, air traffic controllers and meteorologists was conducted in Australia from 1 November 1987 to 31 January 1988 to test this hypothesis. The results of the survey showed that this criterion was satisfied for each dust devil event. Furthermore, the results were consistent with the idea that convective downdrafts play an important role in initiating dual devils. In strongly convective conditions there were two preferred heights attained by the dust—one at ≈0.09h(the height of the convergence wall between cells) and the other ≈0.51h(the height at which the vertical divergence of the updraft changes sign). The number density in these conditions is ≈4 per area of h2. The survey showed that dust devils on density currents have a different geometry; they have diameters five times ...
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
