Models
Modelling Philosophy
All investigations are based on a systems approach to the developing of sound model components whereby the essential physics is combined with practical representations of the natural environment. An emphasis is placed on calibration of models to determine the valid ranges of empirical parameters and the verification, wherever possible, that models are representing the real situation. Parameter sensitivity testing is an integral part of any analysis. Best available scientific techniques are selected but an engineering philosophy underpins the implementation so that practical outcomes are obtained which are targeted at client needs. Quality assurance is an essential component of the model development and is manifested in detailed documentation of model design and operation, culminating in evidence of model performance.
Because of a desire to maintain the highest standards of technical credibility, all investigation methodology detail is fully disclosed to clients, who are then encouraged to obtain independent reviews. Workshops and multi-disciplinary approaches are preferred when exploring untried areas. Collaboration is sought with other research or Government groups wherever possible to gain mutual benefits. Formal publishing of techniques has followed as time permits.
Models in Use
The following provides an overview of the main numerical models that are currently available and have been used extensively over the past 25 years:
SEAtide - Real-Time Storm Tide Prediction and Warning Model
A hurricane storm surge forecasting environment capable of rapid (Monte Carlo) scenario generation, mapping and display. Implementations have included the Australian Bureau of Meteorology (Northern Territory and Queensland), Townsville City and the Queensland State Government as well as corporate insurance clients.
SEAsim - Tropical Cyclone Surge and Tide Simulation
A discrete Monte-Carlo statistical model employing tide generation and a parametric hurricane surge model, which can be applied to arbitrary coastal areas. This model has been used to provide Return Period water level estimates along the entire tropical coastline of Australia (Cape Byron to Cape Leeuwin). SEAsim (Harper and Mason 2016, 2020) is built on the SEAtide model framework and expands on the earlier SATSIM model capabilities (Harper and McMonagle 1983).
SEArapt - Risk Assessment Planning Tool
A general coastal hazard risk assessment and adaptation cost/benefit sensitivity model capable of estimating the financial impacts of community planning decisions. The model is generalised and can be used to represent any coastal location with or without considerations of projected future climate change.
MMUSURGE - Hydrodynamic Storm Surge Model
A general 2-D (depth integrated) implicit finite difference model of hurricane storm surge with the capacity for nesting, overland flooding, reef and barrier sub-grid features. This highly efficient model was developed in the 1990s by the Marine Modelling Unit at James Cook University and has been used extensively for deterministic storm surge modelling throughout Australia (Bode and Mason 1992; Harper 2001, 2010). The model has been extensively validated against historical tropical cyclone events across Australia.
WAMGBR - Spectral Wave Model
A general 3rd gen 2-D spectral wave model based on WAM Cycle 3 but with very efficient implicit finite difference propagation and the capacity for nesting and reef and barrier sub-grid features. This model was developed in the 1990s by the Marine Modelling Unit at James Cook University and has been used extensively for deterministic hurricane wave modelling throughout Australia (Hardy et al. 2001; Harper 2001). The model has been extensively validated against historical tropical cyclone events across Australia and also in the US Gulf of Mexico (McConochie et al. 2010).
SURGE - Hydrodynamic Storm Surge Model
A general 2-D (depth integrated) explicit finite difference model of hurricane storm surge with the capacity for overland flooding. This model was developed in the late 1970s and has been used extensively for deterministic storm surge modelling throughout Australia (Sobey et al. 1977; Sobey and Harper 1977; Harper et al. 1978; Sobey et al. 1980; Harper and Sobey 1983; Harper et al. 2001). The model is generalised and can be used to represent any coastal location, including reef features.
HARBREM - Rubble Mound Breakwater Model
This empirical model assists in the design of mass-armoured rubble mound breakwaters for harbour protection works (Bremner et al. 1987). The model is based on hydraulic model testing of highly porous breakwater configurations and was developed with the assistance of a Marine Sciences and Technologies Research Grant.
SPECT/ADFA1 - Spectral Hurricane Wave Model
A discrete second-generation 2-D spectral energy model of the generation and propagation of hurricane generated waves (Young and Sobey 1986; Young 1987). This model has been used extensively for deterministic modelling of offshore design criteria in Western Australia and underpins the parametric wave sub-model of SATSIM. The model has been extensively calibrated against more than 30 hurricanes in Australian waters and has also been used for investigations in the Arabian Sea and for the design of a real-time early warning system for port operations (Harper et al. 1993, Harper and Nugent 1994).
SEACatD - Catastrophe Model: Deterministic
A community impact model of the effects of extreme tropical cyclone winds on domestic buildings (in collaboration with the James Cook Cyclone Testing Station, Townsville, as part of the Tropical Cyclone Coastal Impacts Program - TCCIP).
References
Bode L. and Mason L.B. (1992) Numerical modelling of tidal currents in the southern Great Barrier Reef. Marine Modelling Unit, Dept of Civil and Systems Engin., James Cook University, Feb, 49pp.
Bremner W, Harper B A and Foster D N, (1987) The Design and Construction of a Mass Armoured Breakwater at Hay Point, Australia, Proc Seminar on Unconventional Rubble Mound Breakwaters, NRCC, Ottowa, Sept.
Hardy, T.A., Mason, L.B. and McConochie, J.D. (2001) A wave model for the Great Barrier Reef. Ocean Engineering, 28 (1), 45-70.
Harper B A, Sobey R J and Stark K P, (1978) Sensitivity Analysis of a Tropical Cyclone Surge Model, in Noye B J (ed) Numerical Simulation of Fluid Motion, North-Holland, pp 371-381.
Harper B A and Sobey R J, (1983) Open Boundary Conditions for Open Coast Hurricane Storm Surge, Coastal Engineering 7, pp 41-60.
Harper B A and McMonagle C J, (1983) Greater Darwin Storm Surge Study - Part 3: "Extreme Water Level Frequencies", Northern Territory Department of Lands under direction Maritime Works Branch Department of Housing and Construction, Blain Bremner and Williams Pty Ltd, Sept, 120 pp.
Harper B A and McMonagle C J, (1985) Storm Tide Statistics - Methodology, Beach Protection Authority of Queensland, Blain Bremner and Williams Pty Ltd, Jan, 120 pp.
Harper B A, Lovell K F, Chandler B D and Todd D J, (1989) The Derivation of Environmental Design Criteria for Goodwyn 'A' Platform, Proc 9th Aust Conf Coastal and Ocean Engin, I E Aust, Dec.
Harper B A, Mason L B and Bode L, (1993) Tropical Cyclone Orson - A Severe Test for Modelling, Proc 11th Australian Conference on Coastal and Ocean Engineering, IEAust, Townsville, Aug, pp. 59-64.
Harper B A, and Nugent S W, (1994) Port Early Warning System Concepts, Proc Asian and Australasian Ports and Harbours Conf, EADA, Kuala Lumpur, Sept.
Harper B A, (1996a) Risk Modelling of Cyclone Losses, Proc Annual Engineering Conf, IEAust, Darwin, April.
Harper B A, (1996b) The Application of Numerical Modelling in Natural Disaster Risk Management, Proc Conf Natural Disaster Reduction NDR'96, Gold Coast, Sep.
Harper B A, (1997) Numerical Modelling of Extreme Tropical Cyclone Winds, Proc 4th Asia Pacific Sympos on Wind Engin, Gold Coast, July.
Harper B A and Robinson D A, (1997) Storm Tide Threat in Queensland, Proc 13th Australasian Conf Coastal and Ocean Engin, IPENZ/IEAust, Christchurch, Sept.
Harper B A and Callaghan J, (1998) Modelling of Severe Thunderstorms in South East Queensland. Proc. Sixth Australian Severe Storms Conference, Bureau of Meteorology, Brisbane, Aug.
Harper B.A. (ed.), (2001) Queensland climate change and community vulnerability to tropical cyclones - ocean hazards assessment - stage 1, Report prep by Systems Engineering Australia Pty Ltd in association with James Cook University Marine Modelling Unit, Queensland Government, March, 375pp. [available from: https://legacy.longpaddock.qld.gov.au/about/publications/vulnerabilitytocyclones/index.html]
Harper B.A., Gourlay M.R. and Jones C.M. (2001) Storm tide risk assessment for the Cocos (Keeling) Islands, Proc 15th Australasian Conference on Coastal and Ocean Engin, Coasts & Ports 2001, Engineers Australia, Gold Coast, Sept, 75-80.
Harper B.A. (2010) Modelling the Tracy storm surge - implications for storm structure and intensity estimation. Proc. Cyclone Tracy Special Session, AMOS Conference 2008, Australian Meteorological and Oceanographic Journal, 60, 187-197, Sept. [Available online at: http://www.bom.gov.au/amoj/docs/2010/harper.pdf ] <\p>
Harper B.A. and Mason L.B. (2016) A tropical cyclone wind event data set for Australia. Proc. 18th Australasian Wind Engineering Society Workshop, 6-8 July, McClaren Vale, SA. [Available from http://www.systemsengineeringaustralia.com.au/download/AWES%2018%20Harper%20and%20Mason.pdf ]
Harper B.A. and Mason L.B. (2020) A Tropical Cyclone Wind, Wave and Storm Tide Risk Design and Warning Toolbox for Australia. Coastal Engineering Proceedings, (36v), management.5. ,Oct, https://doi.org/10.9753/icce.v36v.management.5 and https://youtu.be/pssgiYdkEbM
Holland, G J, (1980) An Analytic Model of the Wind and Pressure Profiles in Hurricanes. Mon. Wea. Rev., 108, 1212-1218.
McConochie, J.D., Stroud, S.A. and Mason, L.B. (2010) Extreme hurricane design criteria for LNG developments: experience using a long synthetic database. Proc. Annual Offshore Technology Confereece, OTC-20732-PP.
Sobey R J, Harper B A and Stark K P, (1977) Numerical Simulation of Tropical Cyclone Storm Surge, Department of Civil and Systems Engineering, Research Bulletin No. CS14, James Cook University, May, 300 pp.
Sobey R J and Harper B A, (1977) Tropical Cyclone Surge Penetration Across the Great Barrier Reef, Proc 3rd Aust Conf Coastal and Ocean Engg, I E Aust, Melb, pp 58-63.
Sobey R J, Harper B A and Mitchell G M, (1980) Numerical Modelling of Tropical Cyclone Storm Surge, Proc 17th International Conf Coastal Engg, Sydney, pp 725-745.
Young I R and Sobey R J, (1986) Hurricane Wind Waves - A Discrete Spectral Model. ASCE Journal of Waterway, Port, Coastal and Ocean Engineering, Vol. 112, No. 3, 370-389.
Young I R, (1987) A General Purpose Spectral Wave Prediction Model. Res. Rep. No. 16, Univ College, Australian Defence Force Academy, Canberra, Jan.
