NOAA Coral Reef Watch Graphs and Bleaching Alerts

This web page provides access to 2000-present sea surface temperature (SST) and coral bleaching Degree Heating Weeks (DHW) time series graphs, data, and the summaries of 2003-present satellite bleaching alerts issued from NOAA Coral Reef Watch's (CRW) near-real-time Satellite Bleaching Alert (SBA) System for 24 selected reef sites around the globe. Users are referred to CRW's 50km global satellite SST field and Coral Bleaching DHW from which the SST and DHW time series are extracted, respectively, and CRW's SBA website for details. The data files are in ASCII (text) format. Click here to view the description for the data files. The summary of past alerts for each reef site includes the dates of issuance and their alert levels along with the sea surface temperature, bleaching HotSpot anomaly, and Degree Heating Week values at the time of issuance. The time and duration of these alerts and their thermal stress levels are also marked and color-coded on the SST/DHW time series graphs. The summarized alerts are available starting from February 2, 2003. The SBA became operational on July 24, 2005 and earlier alerts shown in summaries and on time series graphs were produced retrospectively.

The SST and DHW time series and the information contained in the alerts are extracted from 50 km water pixels surrounding or close to these reef sites. A map showing a particular reef site and its satellite pixel is accessible by clicking on the reef name. This web page and the Coral Bleaching Virtual Stations provide various information for the same 24 selected reef sites.

The time of peak bleaching season varies among ocean basins and hemispheres. Generally, the peak season for both the northern Atlantic Ocean and the northern Pacific Ocean is July-September and for both the southern Atlantic Ocean and southern Pacific Ocean is January-March. The peak season for the northern Indian Ocean is April-June and for the southern Indian Ocean is January-April.