The spatial–temporal variability of chlorophyll-a across the eastern Indonesian seas region using sentinel-3 OLCI

The Eastern Indonesian Seas are among the most biodiverse maritime habitats. Changing chlorophyll-a concentrations affects primary productivity, and ecological changes. Monitoring chlorophyll levels is crucial for ocean health and nutrient availability. High-resolution ocean color data from the Sentinel-3 Ocean and Land Color Instrument allows for global chlorophyll monitoring. This study analyzes how monsoon activity affects chlorophyll distribution in eastern Indonesian oceans. Monthly Chlorophyll-a Concentration Retrieval with Sentinel-3 Ocean and Land Color Instrument Imageries was utilized to study the Eastern Indonesian Seas region from 2016–2021. The Case-2 Regional Coast Color processor, a neural network-based algorithm, was applied to all images for atmospheric correction processing and for ocean color products’ extraction. The distribution of chlorophyll-a in the eastern region of Indonesia varies significantly, with average concentrations ranging from 0.09 to 0.45 mg/m3 in the Banda Sea, Arafura Sea, Flores Sea, and Timor Sea. The Asian-Australian Monsoon System significantly impacts these patterns, with chlorophyll-a levels increasing during the Southeast Monsoon and decreasing during the Northwest Monsoon, particularly in areas with annual upwelling events.