12:00 〜 12:15
[ACG41-18] Advancing Shallow Coral Reef Monitoring: A Nonlinear Spectral Unmixing Approach for Simultaneous Detection of Benthic Cover, Water Quality, and Bathymetry
キーワード：Remote sensing, PlanetScope, Spectral unmixing, Benthic cover, Water quality, Coral reef
In 2024, NOAA confirmed the fourth and most widespread global coral bleaching event, affecting 77% of coral reefs worldwide. This underscores the urgent need for accurate data to support reef conservation. Water quality is a critical factor in the health of marine ecosystems, particularly in coral reefs and seagrass meadows. High concentrations of turbidity restricts light penetration, consequently limiting coral reef distribution predominantly to shallow, nearshore environments. Numerous previous remote sensing studies have demonstrated efficacy in mapping coastal water quality parameters. However, this study aims to develop an integrated methodology for simultaneously estimating shallow water benthic cover, water constituent concentrations (e.g., total suspended solids (TSS), turbidity (T), or chlorophyll-a (Chl-a)), and depth from high-resolution satellite imagery of reef environments. This research employs a sophisticated approach that combines seven-band imagery from PlanetScope with a nonlinear unmixing technique and radiative transfer (RT) theory.
The primary objective is to quantify various benthic cover types such as sand, corals, seagrass, brown algae, and reef rock while also evaluating water quality parameters (TSS, T, and Chl-a) and determining water depth. This approach offers a comprehensive analysis of both seafloor composition and water column characteristics. The new technique was applied into reef area near the Todoroki River mouth, Ishigaki Island, Japan. The accuracy of these estimates was validated against in-situ measurements collected in September 2023, with ongoing refinements aimed at improving model precision. This research contributes to advancing coral reef monitoring methodologies and supports efforts toward effective conservation.
The primary objective is to quantify various benthic cover types such as sand, corals, seagrass, brown algae, and reef rock while also evaluating water quality parameters (TSS, T, and Chl-a) and determining water depth. This approach offers a comprehensive analysis of both seafloor composition and water column characteristics. The new technique was applied into reef area near the Todoroki River mouth, Ishigaki Island, Japan. The accuracy of these estimates was validated against in-situ measurements collected in September 2023, with ongoing refinements aimed at improving model precision. This research contributes to advancing coral reef monitoring methodologies and supports efforts toward effective conservation.