Optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperature
Coral bleaching events have become more frequent in recent years due to the impact of widespread marine heatwaves. The Coral Reef Watch (CRW) program, part of the National Oceanic and Atmospheric Administration (NOAA), assesses bleaching risk by considering measures of daily coral heat stress (Hotsp...
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Frontiers Media S.A.
2024-11-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2024.1438087/full |
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| author | Bailu Liu Bailu Liu Bailu Liu Shawna A. Foo Lei Guan Lei Guan |
| author_facet | Bailu Liu Bailu Liu Bailu Liu Shawna A. Foo Lei Guan Lei Guan |
| author_sort | Bailu Liu |
| collection | DOAJ |
| description | Coral bleaching events have become more frequent in recent years due to the impact of widespread marine heatwaves. The Coral Reef Watch (CRW) program, part of the National Oceanic and Atmospheric Administration (NOAA), assesses bleaching risk by considering measures of daily coral heat stress (Hotspot, HS) and accumulated heat stress (Degree Heating Week, DHW). However, there is a mismatch between coral bleaching alerts through satellite monitoring and records of coral bleaching in the South China Sea (SCS) and its surrounding seas in the historical database. Through comparison with field records of bleaching events in the SCS, this study examined the optimization of the DHW under a fixed or variable HS threshold, evaluating the accuracy of coral bleaching monitoring through a range of evaluation indices, including the Peirce Skill Score (PSS) and the Area Under the Curve (AUC). Our results show that when the DHW index was calculated based on the current operational HS threshold (1°C), reducing the DHW threshold from 4°C to 1.86°C-weeks significantly improved PSS from 0.17 to 0.66, and AUC from 0.58 to 0.83. Further, by optimizing both HS and DHW, evaluation statistics were further improved, with the PSS increasing to 0.71 and the AUC increasing to 0.85. While both methods could significantly optimize the operational bleaching alert level for the SCS, the results suggest that optimization of both the HS and DHW thresholds is better than optimizing DHW alone. As marine heatwaves become more frequent, accurately predicting when and where coral bleaching is likely to occur will be critical to improving the estimation of regional coral stress due to climate change and for understanding coral reefs’ response to recurrent bleaching events. |
| format | Article |
| id | doaj-art-8ad4cfd8f6d54042a53b87b98f5f85df |
| institution | OA Journals |
| issn | 2296-7745 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj-art-8ad4cfd8f6d54042a53b87b98f5f85df2025-08-20T01:54:16ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452024-11-011110.3389/fmars.2024.14380871438087Optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperatureBailu Liu0Bailu Liu1Bailu Liu2Shawna A. Foo3Lei Guan4Lei Guan5College of Marine Technology, Faculty of Information Science and Engineering, Ocean University of China/Laboratory for Regional Oceanography and Numerical Modeling, Qingdao Marine Science and Technology Center, Qingdao, ChinaSchool of Life and Environmental Sciences, the University of Sydney, Sydney, NSW, AustraliaSanya Oceanographic Institution, Ocean University of China/SANYA Oceanographic Laboratory, Sanya, ChinaSchool of Life and Environmental Sciences, the University of Sydney, Sydney, NSW, AustraliaCollege of Marine Technology, Faculty of Information Science and Engineering, Ocean University of China/Laboratory for Regional Oceanography and Numerical Modeling, Qingdao Marine Science and Technology Center, Qingdao, ChinaSanya Oceanographic Institution, Ocean University of China/SANYA Oceanographic Laboratory, Sanya, ChinaCoral bleaching events have become more frequent in recent years due to the impact of widespread marine heatwaves. The Coral Reef Watch (CRW) program, part of the National Oceanic and Atmospheric Administration (NOAA), assesses bleaching risk by considering measures of daily coral heat stress (Hotspot, HS) and accumulated heat stress (Degree Heating Week, DHW). However, there is a mismatch between coral bleaching alerts through satellite monitoring and records of coral bleaching in the South China Sea (SCS) and its surrounding seas in the historical database. Through comparison with field records of bleaching events in the SCS, this study examined the optimization of the DHW under a fixed or variable HS threshold, evaluating the accuracy of coral bleaching monitoring through a range of evaluation indices, including the Peirce Skill Score (PSS) and the Area Under the Curve (AUC). Our results show that when the DHW index was calculated based on the current operational HS threshold (1°C), reducing the DHW threshold from 4°C to 1.86°C-weeks significantly improved PSS from 0.17 to 0.66, and AUC from 0.58 to 0.83. Further, by optimizing both HS and DHW, evaluation statistics were further improved, with the PSS increasing to 0.71 and the AUC increasing to 0.85. While both methods could significantly optimize the operational bleaching alert level for the SCS, the results suggest that optimization of both the HS and DHW thresholds is better than optimizing DHW alone. As marine heatwaves become more frequent, accurately predicting when and where coral bleaching is likely to occur will be critical to improving the estimation of regional coral stress due to climate change and for understanding coral reefs’ response to recurrent bleaching events.https://www.frontiersin.org/articles/10.3389/fmars.2024.1438087/fullcoral bleaching monitoringSouth China Seasea surface temperaturedegree heating weekthermal stress |
| spellingShingle | Bailu Liu Bailu Liu Bailu Liu Shawna A. Foo Lei Guan Lei Guan Optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperature Frontiers in Marine Science coral bleaching monitoring South China Sea sea surface temperature degree heating week thermal stress |
| title | Optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperature |
| title_full | Optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperature |
| title_fullStr | Optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperature |
| title_full_unstemmed | Optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperature |
| title_short | Optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperature |
| title_sort | optimization of thermal stress thresholds on regional coral bleaching monitoring by satellite measurements of sea surface temperature |
| topic | coral bleaching monitoring South China Sea sea surface temperature degree heating week thermal stress |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2024.1438087/full |
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