The NOAA Coral Reef Watch bleaching prediction system indicates that there will be some bleaching in the Caribbean later this year, but bleaching will probably not be severe. Currently, the forecast system suggests that bleaching may be more severe in the Windward Islands of the Lesser Antilles than was predicted last month. The potential for widespread bleaching in the Northwestern Hawaiian Islands has lessened. Some bleaching remains likely around Papua-New Guinea, through the Northern Mariana Islands and Micronesia, to Japan. The following figure shows the current Global 4-month Coral Bleaching Outlook through December 2008.
In a normal year, the model will forecast no potential for bleaching. When sea surface temperatures are forecast to exceed bleaching thresholds for a long enough period to cause bleaching, the outlook maps display the bleaching potential. Actual conditions may vary due to subsequent changes in climatic conditions or weather patterns.
Pacific Bleaching Outlook:
Fortunately, the forecast for abnormally high temperatures has lessened in the North Pacific, so the potential for bleaching in the Northwestern Hawaiian Islands (NWHI) is not as high as the system forecast in July.
There is also a potential for some bleaching elsewhere in the North Pacific that may influence reefs from Papua-New Guinea, through the Northern Mariana Islands and Micronesia, and up to Japan. Bleaching across this region is likely to be mild, similar to that expected in the Caribbean this year. The reduced threat in the Ryukyus suggests that the current high temperatures will hopefully subside shortly.
The model now calls for unusually high temperatures along the Pacific coast of Mexico. There is a potential for severe bleaching around the Baja peninsula. However, we are not yet sure how well the model performs in a semi-enclosed water mass such as the Gulf of California.
Caribbean Bleaching Outlook:
The forecast system indicates that there is a potential for bleaching across the Caribbean basin in 2008, but it is not likely to be severe. The potential for widespread bleaching has increased for the Windward Islands and perhaps along the coasts of Nicaragua and Colombia. The following figure shows the current Caribbean 4-month Coral Bleaching Outlook through December 2008.
About the Forecast System:
The forecast system uses NOAA experimental sea surface temperature (SST) forecasts (Linear inverse Modeling) to develop maps of potential coral bleaching severity during the upcoming bleaching season (August to October for the northern hemisphere and January-March for the southern hemisphere). While NOAA’s Coral Reef Watch Program has been using satellite SST data to alert managers and scientists around the world of the risk of coral bleaching, this forecast system now includes longer-range SST forecasts.
The new system was developed by scientists in NOAA’s Coral Reef Watch in Silver Spring, MD and NOAA Earth Science Research Laboratory's Physical Science Division in Boulder, Colo., with funding from the NOAA Climate Program Office’s Sectoral Applications Research Program and NOAA’s Coral Reef Conservation Program.
The outlook is based on a composite of forecasts for all weeks included in the time period indicated in the outlook figure. Because of the nature of the forecast system, events of similar magnitude are often underpredicted at longer forecast lead-times. Their purpose is not to provide exact predictions at any particular reef locations, but to provide general patterns of bleaching potential.
