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	Degree Heating Weeks	海洋色クロロフィルa
分野	海洋学	海洋学
系統	Process / pipeline	Process / pipeline
提唱年	2003	1978
提唱者	NOAA Coral Reef Watch	Remote Sensing Community
種類	thermal-metric	bio-optical
原典	Liu, G., Strong, A. E., & Skirving, W. (2003). Remote sensing of sea surface temperatures during 2002 Great Barrier Reef coral bleaching. EOS Transactions, 84(15), 137-141.	Gordon, H. R., & Morel, A. Y. (1983). Remote Assessment of Ocean Color for Interpretation of Satellite Visible Imagery. Springer-Verlag.
別名	DHW, Thermal Stress Index	Chlorophyll-a Retrieval, Ocean Productivity Monitoring
関連	3	3
概要	Degree Heating Weeks (DHW) is a thermal stress metric that quantifies accumulated heat exposure above a coral bleaching threshold, computed from satellite sea surface temperature data. Developed by NOAA's Coral Reef Watch program in 2003, DHW provides a standardized index for predicting and monitoring coral bleaching stress globally. The metric combines intensity and duration of thermal anomalies to estimate cumulative physiological stress on coral colonies.	Ocean color remote sensing is the primary global method for retrieving seawater chlorophyll-a concentrations and phytoplankton productivity from satellite sensors. Based on bio-optical principles established in the 1970s, ocean color algorithms convert satellite spectral reflectance measurements into estimates of chlorophyll-a pigment concentration. This method enables global-scale, real-time monitoring of oceanic primary productivity and plankton dynamics.