Reef-Scale Thermal Stress Monitoring of Coral Ecosystems: New 5-km Global Products from NOAA Coral Reef Watch

The U.S. National Oceanic and Atmospheric Administration (NOAA) Coral Reef

Watch (CRW) program has developed a daily global 5-km product suite based on satellite

observations to monitor thermal stress on coral reefs. These products fulfill requests from

coral reef managers and researchers for higher resolution products by taking advantage of

new satellites, sensors and algorithms. Improvements of the 5-km products over CRW’s

heritage global 50-km products are derived from: (1) the higher resolution and greater data

density of NOAA’s next-generation operational daily global 5-km geo-polar blended sea

surface temperature (SST) analysis; and (2) implementation of a new SST climatology

derived from the Pathfinder SST climate data record. The new products increase near-shore

coverage and now allow direct monitoring of 95% of coral reefs and significantly reduce

data gaps caused by cloud cover. The 5-km product suite includes SST Anomaly, Coral

Bleaching HotSpots, Degree Heating Weeks and Bleaching Alert Area, matching existing

CRW products. When compared with the 50-km products and in situ bleaching observations

for 2013–2014, the 5-km products identified known thermal stress events and matched

bleaching observations. These near reef-scale products significantly advance the ability of

coral reef researchers and managers to monitor coral thermal stress in near-real-time.