Detecting and monitoring 2001 coral reef bleaching events in Ryukyu Islands, Japan using satellite bleaching HotSpot remote sensing technique

Widespread coral bleaching due to anomalously high water temperature was observed in the Ryukyu Islands, Japan during the summer of 2001. The U.S. National Oceanic and Atmospheric Administration's (NOAA) near real-time coral bleaching HotSpot early warning products, derived from satellite sea surface temperature (SST), showed that extraordinarily warm water started to cover the Northwest Pacific region beginning in late-June. This thermal stress continued to accumulate for over two months into early September. Coral bleaching early warnings were initially issued to the region (informally by NOAA via e-mail) early in the summer season based on the satellite observations. The comparison between the satellite SSTs and several in situ temperature observations in the region shows that the NOAA satellite HotSpot technique was remarkably informative in showing the onset, development, and dissipation of the warming event.