Analysis of a southerly buster event and associated solitary waves
Shuang Wang A B D , Lance Leslie A , Tapan Rai A , Milton Speer A and Yuriy Kuleshov CA University of Technology Sydney, Sydney, NSW, Australia.
B Bureau of Meteorology, PO Box 413, Darlinghurst, NSW 1300, Australia.
C Bureau of Meteorology, Melbourne, Vic., Australia.
D Corresponding author. Email: shuang.wang@bom.gov.au
Journal of Southern Hemisphere Earth Systems Science 69(1) 205-215 https://doi.org/10.1071/ES19015
Submitted: 19 May 2019 Accepted: 7 October 2019 Published: 11 June 2020
Journal Compilation © BoM 2019 Open Access CC BY-NC-ND
Abstract
This paper is a detailed case study of the southerly buster of 6–7 October 2015, along the New South Wales coast. It takes advantage of recently available Himawari-8 high temporal- and spatial-resolution satellite data, and other observational data. The data analyses support the widespread view that the southerly buster is a density current, coastally trapped by the Great Dividing Range. In addition, it appeared that solitary waves developed in this event because the prefrontal boundary layer was shallow and stable. A simplified density current model produced speeds matching well with observational southerly buster data, at both Nowra and Sydney airports. Extending the density current theory, to include inertia-gravity effects, suggested that the solitary waves travel at a speed of ∼20% faster than the density current. This speed difference was consistent with the high-resolution satellite data, which shows the solitary waves moving increasingly ahead of the leading edge of the density current.
Additional keywords: coastally trapped disturbance, density currents.
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