Notice: CRW's twice-weekly 50 km products will update around 2 pm on Mondays and Thursdays (U.S. Eastern Time) starting from 1 February 2016, using a new 50 km SST analysis. Click here to see details.
50-km Degree Heating Week
clickable global map of degree heating weeks
DHWs in Mediterranean and Red Sea DHWs around India DHWs east of Japan DHWs around Hawaii DHWs around Central America DHWs West of Africa DHWs in Mediterranean and Red Sea DHWs around southern Africa DHWs in the southern Indian Ocean DHWs around Australia DHWs in the South Pacific DHWs west of South America DHWs east of Brazil DHWs around southern Africa
Click on the image to zoom in.

Current images: Global | E.Hem. | W.Hem. | Pacific | Caribbean | Coral Triangle

Data Formats Available

images Image Archives
Regional imagery and image archives from OSDPD.
Google Earth Google Earth
All of our satellite data products are available on Google Earth.
Virtual Stations 50-km Virtual Stations
Imagery, graphs, ASCII data, and e-mail alerts for reef pixels around the world.
animations Animations
Data animations and downloadable animated GIF files from OSDPD.
HDF data HDF data files
Raw data in Hierarchical Data Format (HDF), with free NOAA viewing software.

The NOAA Coral Reef Watch (CRW) twice-weekly 50-km satellite coral bleaching Degree Heating Week (DHW) product presented here shows accumulated thermal stress, which can lead to coral bleaching and death. The scale goes from 0 to 16 °C-weeks. Spatial resolution is one-half degree precisely. The DHW product accumulates the instantaneous bleaching thermal stress (measured by Coral Bleaching HotSpots) during the most-recent 12-week period. It is directly related to the timing and intensity of coral bleaching. Significant coral bleaching usually occurs when DHW values reach 4 °C-weeks. By the time DHW values reach 8 °C-weeks, widespread bleaching is likely and significant mortality can be expected.

Additional description in the 50-km products tutorial.
Technical details on the methodology page and in Liu et al. 2013.