NOAA Coral Reef Watch (CRW) has been applying satellite remote sensing to monitor coral reef environments for more than a decade. CRW’s operational satellite sea surface temperature (SST)-based data products monitor global current coral reef environmental conditions to quickly identify areas at risk of thermally-induced mass coral bleaching. Mass coral bleaching events have been well correlated with thermal stress. In the event of severe thermal stress, disease and mortality may follow. Severe bleaching events have dramatic long-term ecological and social impacts. Continuous monitoring of bleaching-level thermal stress at the global scale provides coral reef managers, researchers and stakeholders with critical information to understand, predict, and monitor the development of mass coral bleaching. Taking advantage of continual improvement in NESDIS’ operational satellite SST products, CRW is now developing a next-generation near-real-time satellite decision support system.

http://coralreefwatch.noaa.govApril 2013

NOAA Operational Satellite SST for Monitoring Coral Bleaching Thermal Stress: Coral Reef Watch’s Satellite Decision Support System for Coral Reef Managers

Gang Liu, C. Mark Eakin, Jacqueline L. Rauenzahn, Scott F. Heron, Alan E. Strong, William Skirving, Jianke Li, Tim Burgess, Krystal Repoff, Kelly Howell, John Sapper coralreefwatch@noaa.gov, NOAA Coral Reef Watch, E/RA3, NCWCP, 5830 University Research Court, College Park, MD 20740 USA

The only satellite-based system available for U.S. and global coral reef management

Early Warning System for Mass Coral Bleaching Events(Current system: 50-km, twice-weekly; Next-generation system: 5-km, daily)

Bleaching Alert Area Degree Heating Weeks

Sea Surface Temperature (SST)

Coral Bleaching HotSpots

SST Anomaly SST Trends

(Map from ReefBase)

(35S-35N)

- Coral reefs thrive in global tropical regions: >18°C (35S-35N)

- Cover less than 1% of the Earth’s surface - Provide habitat for 25% of all known marine species- Support approximately 500 million people- Require satellite remote sensing for global coverage,

reaching remote areas, synoptic views of large areas, and real-time and/or near-real-time monitoring

> 18ºC

CRW Satellite Virtual Stations 2001-2012 Annual Composites (Bleaching Alert Area)2001 2007

2002

2003

2004

2005

2006

2008

2009

2010

2011

2012

Increasing Bleaching Thermal StressWorldPacificCaribbean

% R

eefs

wit

h Bl

each

ing

Stre

ss

Year

80Bleaching Thermal Stress Based on Historical Pathfinder SST Data

60

40

20

01985 1990 1995 2000 2005

SST

TimeWeek-0 Week-12

SST Bleaching threshold (MMMSST+1ºC)

Maximum of the Monthly Mean SST

Climatology (MMMSST)b ca d

Hotspot

Degree Heating Weeks

CRW Satellite Bleaching Thermal Stress Monitoring Algorithms

Stress Level     Definition     Potential Bleaching IntensityNo Stress HotSpot ≤ 0 No Bleaching Bleaching Watch 0 < HotSpot < 1 Bleaching Warning 1 ≤ HotSpot and 0 < DHW < 4 Possible Bleaching Bleaching Alert Level 1 1 ≤ HotSpot and 4 ≤ DHW < 8 Bleaching Likely Bleaching Alert Level 2 1 ≤ HotSpot and 8 ≤ DHW

Mortality Likely

Bleaching Alert Area

Degree Heating Weeks

( HotSpot value duration )12 weeks

1°C

HotSpots: Instantaneous thermal stressCumulative measure of thermal stress intensity and duration during the most-recent 12-week period

≥ 4 DHWs Coral bleaching is expected≥ 8 DHWs Widespread bleaching and mortality are expected

Coral Reef Watch: a NOAA/NESDIS program, funded predominantly by the NOAA Coral Reef Conservation Program (CRCP), integrates scientists from the Center for Satellite Applications and the Research (STAR) and Office of Satellite and Product Operations (OSPO).