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

Gang Liu,C Eakin,Timothy Burgess,Jianke Li,William Skirving,Frank Muller-Karger,Andy Harris,Scott Heron,Alan Strong,Alexander Ignatov,Susan Lynds,John Sapper,Eileen Maturi,Erick Geiger,Liane Guild,Jacqueline De La Cour,Maria Vega-Rodriguez

doi:10.3390/rs61111579

Abstract

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.

Highlights

Shallow-water tropical coral reef ecosystems are often compared with rainforests because of their high biodiversity and complexity
We describe National Oceanic and Atmospheric Administration (NOAA)/NESDIS’ daily 5-km sea surface temperature (SST) analysis and development of the 5-km climatology, introduce Coral Reef Watch (CRW)’s daily global 5-km product suite derived from these new inputs, show examples of its improvements over the heritage 50-km products and discuss the performance of the
The 5-km geo-polar blended night-only SST analysis, released in March, 2013, is derived from SST measurements taken by a combination of geostationary and polar-orbiting environmental satellites operated by NOAA, the Japan Meteorological Agency (JMA) and the European

Summary

Introduction

Shallow-water tropical coral reef ecosystems are often compared with rainforests because of their high biodiversity and complexity. These bio-geological structures have formed over thousands of years by small, colonial organisms dependent on microscopic algal partners. Mass coral bleaching events due to anomalously warm ocean water have increased in frequency and severity [1] and become one of the most significant contributors to the deterioration of global coral reef ecosystems [2]. Extensive bleaching events have dramatic long-term ecological and social impacts, including loss of reef-building corals, changes in benthic habitat, changes in associated fish populations [10] and economic loss [11]. As the climate continues to warm, bleaching is a major threat to the future of coral reefs [12]

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