In the following sections (chapters) of this tutorial, we introduce you to NOAA Coral Reef Watch's (CRW) daily global 5km-resolution satellite coral bleaching heat stress monitoring products, 5km climatology, composites and animations of the daily global 5km products, and the daily 5km Regional Virtual Stations and Satellite Bleaching Alert Email System. All of these products are available on the CRW website, completely free for anyone to use.
CRW's daily global 5km products are based on satellite measurements of sea surface temperature (SST). The first 5km product that we introduce is simply the SST measured all around the world. Next, we compare the current ocean surface temperature with a long-term mean at each location, to calculate an SST Anomaly. The SST Anomaly product tells us where the SST is warmer or cooler than normal, for that location, on the date in question.
In the Coral Bleaching section of this tutorial, you learned that unusually warm SSTs stress corals. Specifically, scientists found that corals become stressed if the SST is above the highest summertime mean temperature. Our Coral Bleaching HotSpot product highlights areas around the world where the SST is above the mean value you would expect to see in the warmest month of the year. Coral bleaching risk increases even more if the water temperature stays warm for a long time. We total the Coral Bleaching HotSpot stress in an area over the prior twelve-week period to calculate the Degree Heating Week (DHW), which provides a cumulative measurement of both the intensity and duration of the heat stress. We then combine the information provided by the current Coral Bleaching HotSpot and DHW to create the Bleaching Alert Area product. The Bleaching Alert Area identifies the current locations, coverage, and potential risk level of coral bleaching heat stress around the world. We also discuss the SST Trend product, which shows the near-term pace and direction of SST variation, and thus coral bleaching heat stress, globally over the past seven days.
We also briefly touch on the Composites and Animations that CRW offers of its daily global 5km satellite coral bleaching heat stress monitoring products.
Finally, we introduce you to the daily 5km Regional Virtual Stations product, which is like having a temperature sensor in the water next to a coral reef, but data are completely based on satellite remote sensing measurements. We also discuss the associated, automated Satellite Bleaching Alert (SBA) Email System.
All of the NOAA CRW 5km data products discussed in this tutorial are updated daily, so you can always see the current environmental conditions around the globe. We call this "near real-time" monitoring because there is only a brief time delay with our 5km-resolution satellite products.