The June 2016 Australian East Coast Low: Importance of Wave Direction for Coastal Erosion Assessment
by Thomas R. Mortlock , Ian D. Goodwin, John K. McAneney and Kevin Roche
In June 2016, an unusual East Coast Low storm affected some 2000 km of the eastern seaboard of Australia bringing heavy rain, strong winds and powerful wave conditions. While wave heights offshore of Sydney were not exceptional, nearshore wave conditions were such that beaches experienced some of the worst erosion in 40 years. Hydrodynamic modelling of wave and current behaviour as well as contemporaneous sand transport shows the east to north-east storm wave direction to be the major determinant of erosion magnitude. This arises because of reduced energy attenuation across the continental shelf and the focussing of wave energy on coastal sections not equilibrated with such wave exposure under the prevailing south-easterly wave climate. Narrabeen–Collaroy, a well-known erosion hot spot on Sydney’s Northern Beaches, is shown to be particularly vulnerable to storms from this direction because the destructive erosion potential is amplified by the influence of the local embayment geometry. We demonstrate the magnified erosion response that occurs when there is bi-directionality between an extreme wave event and preceding modal conditions and the importance of considering wave direction in extreme value analyses.
Click on link to read entire article: http://www.mdpi.com/2073-4441/9/2/121
Stationarity of major flood frequencies and heights on the Ba River, Fiji, over a 122-year record
Paper by John McAneney, Robin van den Honert and Stephen Yeo published in International Journal of Climatology.
ABSTRACT: The economic impact of natural disasters on developing economies can be severe with the recovery diverting scarce funds that might otherwise be targeted at development projects and stimulating the need for international aid. In view of the likely sensitivity of low-lying Pacific Islands to anticipated changes in climate, a 122-year record of major flooding depths at the Rarawai Sugar Mill on the Ba River in the northwest of the Fijian Island of Viti Levu is analysed. Reconstructed largely from archived correspondence of the Colonial Sugar Refining Company, the time series comprises simple measurements of height above the Mill floor. It exhibits no statistically significant trends in either frequency or flood heights, once the latter have been adjusted for average relative sea-level rise. This is despite persistent warming of air temperatures as characterized in other studies. There is a strong dependence of frequency (but not magnitude) upon El Niño-Southern Oscillation (ENSO) phase, with many more floods in La Niña phases. The analysis of this long-term data series illustrates the difficulty of detecting a global climate change signal from hazard data, even given a consistent measurement methodology (cf HURDAT2 record of North Atlantic hurricanes) and warns of the strong dependence of any statistical significance upon choices of start and end dates of the analysis.
Bushfire and Natural Hazards CRC shared NSW SES’s Video
It is never safe to drive through floodwaters, no matter the circumstances. Learn from Sonya’s experience in this NSW SES video about why you shouldn’t take your vehicle into floodwaters. The data in the video comes from our research with Risk Frontiers.
Click here to view.
Scientists expect sand flow on East Coast to slow
Several news pieces have been picked up by various sources from a paper published late last year in the Journal of Geophysical Research, Oceans titled “Tropical and extratropical-origin storm wave types and their influence on the East Australian longshore sand transport system under a changing climate” by Ian Goodwin, Thomas Mortlock and Stuart Browning. Thomas Mortlock is a member of the Risk Frontiers’ team and Ian Goodwin and Stuart Browning are members of the Marine Climate Risk Group at Macquarie University.
Click here to read more.
ABC News 24, December 1, 2016
Thomas Loridan talks about his research on categorising impacts of heatwave to strengthen warning.
ABC News, December 1, 2016
Thomas Loridan is interviewed on ABC News – ‘Experts warn against underestimating heatwave threat’.
The Conversation, November 22, 2016
Paul Somerville, from Risk Frontiers at Macquarie University, said this latest earthquake was caused by a normal fault associated with faults in and around the Japan trench subduction zone.
The Australian, August 23, 2016
Shifting sands for councils on responsibility for past projects by Kevin Roche.
Byron Bay in northern NSW, home to one of Australia’s most iconic pieces of coastline, has long been the poster child for disputes in the coastal zone.