Coral Bleaching

These pages provide information on sea surface temperatures for monitoring coral bleaching events in the Great Barrier Reef, Australia.

Forecast Skill

To evaluate the accuracy of model forecasts and provide a measure of the skill of POAMA (Predictive Ocean Atmosphere Model for Australia), retrospective forecasts (hindcasts) of sea surface temperature anomalies (SSTA) are compared to observed SSTA for the same period. SSTA are calculated for both the model forecasts and observed values as the difference between sea surface temperature (SST) values and the relevant climatology. The climatology is the monthly mean SST over the period 1982-2010, computed relative to the start month and lead-time for the model, and removing this from SST values reduces the effects of any model bias (Stockdale 1997). Skill is calculated by correlating model anomalies with observed anomalies. The correlation coefficient (r) is defined as the ratio of the covariance of the sample populations to the product of their standard deviations, with a skill value of 1.0 indicating a perfect fit between model and observed values. For more information see Spillman and Alves (2009) and Spillman (2011).

The plot below shows the skill of the POAMA-2(M24) version ensemble mean SSTA forecasts up to 6 months in advance for the target season January-February-March (JFM) 1982-2010. The observed dataset used here for skill calculations is the monthly Reynolds 0.25° SST data analysis, interpolated onto the ocean model grid. The forecasts exhibit useful skill in some areas for lead-times of 0-5 months. The higher skill in the northern parts compared to the southern area is likely due to the larger influence of tropical variability, principally El Niño Southern Oscillation (ENSO).

Further reading

  • Griesser A.G. and Spillman, C.M. 2012: SST forecast skill of the new intra-seasonal configuration of POAMA-2. CAWCR Res.Lett.,8, 10-16.
  • Spillman C.M., Alves O, Hudson D.A. 2012: Predicting thermal stress for coral bleaching in the Great Barrier Reef using a coupled ocean-atmosphere seasonal forecast model. Int. J. Climatol., DOI: 10.1002/joc.3486.
  • Spillman C.M., 2011: Operational real-time seasonal forecasts for coral reef management. J. Oper. Oceanog., 4, 13-22.
  • Spillman C.M., 2011: Real-time predictions of coral bleaching risk for the Great Barrier Reef: Summer 2010/2011. CAWCR Res. Lett., 6, 34-39.
  • Spillman C. and Alves O., 2009: Dynamical seasonal prediction of summer sea surface temperatures in the Great Barrier Reef. Coral Reefs, 28, 197-206.
  • Spillman C.M., Alves O., and Hudson D.A., 2010: Real-time seasonal SST predictions for the Great Barrier Reef during the summer of 2009/2010. CAWCR Res. Lett., 4, 11-19.
  • Spillman C.M., Alves O., Hudson D.A. and Charles A.N., 2009: POAMA SST predictions for the Great Barrier Reef: Summer 2008/2009. CAWCR Res. Lett., 2, 30-34.

For further information visit POAMA group.

Please be aware that all POAMA forecasts are subject to the Bureau of Meteorology's copyright and disclaimer.