Verification of an ensemble storm surge forecast system for tropical cyclones (#185)
The Bureau of Meteorology has recently implemented a new dynamical system to provide forecasts of storm surge produced by tropical cyclones (TCs). The system is forced using surface wind stress and pressure that is derived from the Bureau of Meteorology's Official Forecast Track and its associated ensemble tracks. This ensemble is produced using the 'DeMaria' method (DeMaria et al., 2009), which takes into account historical TC track and intensity errors. From this, a 200-member ensemble of storm surge models, implemented using the Regional Ocean Modelling System (ROMS) model, provides 72-hour forecasts. These are linearly combined with wave set-up estimates and astronomical tides to produce coastal sea-level forecasts for the tropical and sub-tropical Australian coastline at a spatial resolution of approximately 2 km.
The storm surge component of the system has been described and verified for seven TC case studies using the Bureau of Meteorology 'Best Track' forcing in Greenslade et al (2018). This presentation will provide an overview of the ensemble component of storm surge system, focusing on the verification of the probabilistic forecasts.
- DeMaria, M., Knaff, J.A., Knabb, R., Lauer, C., Sampson, C.R. and DeMaria, R.T., 2009: A New Method for Estimating Tropical Cyclone Wind Speed Probabilities, Weather and Forecasting, 24, 1573-1591.
- Greenslade, D., Taylor, A., Freeman, J., Sims, H., Schulz, E., Colberg, F., Divakaran, P., Velic, M., and Kepert, J., 2018: A First Generation Dynamical Tropical Cyclone Storm Surge Forecast System Part 1: Hydrodynamic model, Bureau Research Report No 31., Bureau of Meteorology, Australia.