The NOAA Coral Reef Watch (CRW) experimental daily global 5-km (0.05 degree) satellite coral bleaching thermal stress monitoring product suite presented here is a next-generation version of the operational twice-weekly 50-km (0.5 degree) monitoring product suite. The high-resolution 5-km suite is based on the NOAA/NESDIS operational daily global 5-km Geo-Polar (geostationary-polar-orbiting) Blended Night-only SST Analysis and currently includes sea surface temperature (SST), SST Anomaly, Coral Bleaching HotSpot, Degree Heating Week (DHW), and Bleaching Alert Area products, along with a 7-day SST Trend product, matching the core operational 50-km satellite products. In February 2015, CRW also added a new Virtual Stations/Gauges product that is based on this 5-km product suite and CRW's Coral Bleaching Thermal Stress Outlook product and is much more comprehensive than the heritage 50-km Virtual Stations product.

Improvements of the 5-km products over the heritage 50-km products are derived from:

This daily global 5-km coral bleaching thermal stress monitoring product suite provides service at or near reef-scales, allowing direct monitoring of 95% of global coral reefs and significantly reducing data gaps caused by cloud cover. The 5-km products now comprise the core of CRW's next-generation Decision Support System (DSS) for coral bleaching management. After further testing and evaluation of the 5-km product suite, CRW's operational 50-km product suite, which has provided 15 years of successful satellite-based monitoring of coral reef ecosystem environmental conditions to global reef communities, will be retired.

Version 2 of the 5-km product suite, presented here, was released on May 5, 2014. CRW's new 5-km Virtual Stations/Gauges were launched February 17, 2015. As noted above, the Version 2 5-km product suite is based on NESDIS' operational daily global 5-km Geo-Polar Blended Night-only SST Analysis, released in March 2013, and uses a new version of the 5-km climatology (available since April 2014).

SST variability is often considerably higher at the much finer 5-km spatial and daily temporal resolutions, when compared with CRW's 50-km twice-weekly SST. Due to resulting day-to-day fluctuations between stress levels in highly-variable locations, the single-day 5-km Bleaching Alert Area product does not consistently and adequately identify potentially harmful thermal stress levels, especially with regard to the impact of accumulated thermal stress. Rather than requiring users to examine the single-day 5-km Bleaching Alert Area product over several days, a 7-day maximum Bleaching Alert Area composite product, updated daily, was introduced in the Version 2 product suite. This 7-day composite product shows the maximum stress level that a pixel has experienced during the most recent seven (7) consecutive days. The data and images are dated on the last day of the 7-day period. Additionally, the 5-km 7-day maximum Bleaching Alert Area composite product is compatible with CRW's operational 50-km twice-weekly Bleaching Alert Area product. The 50-km Bleaching Alert Area product is actually based on a half-week (3 or 4 days) composite of 50-km SSTs, but with much less SST variability due to its much coarser spatial resolution.

In May 2015, CRW released a new 5-km 7-day SST Trend product, updated daily. The 5-km SST Trend provides information on the pace and direction of the SST variation, and thus coral bleaching thermal stress, if present, over the past seven days. Seven daily global SSTs are included in the calculation. Pixels colored in green have insignificant trends, due either to small SST trends (within the range -0.2 to 0.2 °C) or trends that failed the two-tailed Student's-t test for the 20% significance level with five degrees of freedom.

Note that all other Version 2 products presented here are single-day products, updated daily. Images will be 1-2 days behind the current date, however, as data are processed in the early afternoon, U.S. Eastern Time using data from the previous day. For example, data processed on a Wednesday afternoon will include all observations made on Tuesday (independent of time zone) and will carry Tuesday's date.

Development of the next-generation 5-km product suite has been accomplished through a collaboration of NOAA Coral Reef Watch, the University of South Florida, NASA-Ames, the UNEP World Conservation Monitoring Centre, and the Cooperative Institute for Research in Environmental Science, with funding support from the NASA Biodiversity and Ecological Forecasting program, the NOAA Coral Reef Conservation Program, and the NOAA/NESDIS Ocean Remote Sensing Program. The 5-km product suite, which was featured in the NASA Applied Sciences Program's 2013 Annual Report, will undergo continuous improvements.

CRW will continue to produce the current operational 50-km product suite until the 5-km product suite becomes operational. As noted above, there will be some differences between the two product suites in certain areas of the globe, and user discretion is advised. We expect that the 5-km product suite will be more accurate due to the improved data quality, density, spatial and temporal resolutions, and climatology.