Mapping of the Spatio-Spectral Dynamics of Mangrove Chlorophyll Concentrations via Sentinel-2 Satellite Imagery

Mangrove ecosystems play a critical role in maintaining coastal health; however, they are increasingly threatened by anthropogenic activities and climate change. Health assessment is essential for effective conservation efforts. However, traditional remote sensing techniques such as the normalised difference vegetation index (NDVI) may not fully capture the complex physiological processes influencing vegetation health. Therefore, this study investigated chlorophyll (Chl) dynamics in mangroves using remote sensing techniques, including the NDVI and a novel method, the normalised area over reflectance curve (NAOC), via Sentinel-2 satellite imagery during October 2023, and analysed spatial variations in Chl content (CC) via the Google Earth Engine API. NDVI and NAOC-Chl were weakly correlated (0.47), highlighting their complementary roles. The average NDVI and NOAC-Chl values for different species were analysed, and Rhizophora mucronata presented the highest value (NDVI: 0.86 ± 0.08, NOAC: 20.48 ± 4.49.