Comparison of Chlorophyll-a Retrieval from Aqua MODIS Using SeaDAS and ArcGIS of Visakhapatnam Coast at Bay of Bengal

This study mainly focuses on comparing the performance of SeaDAS and ArcGIS in extracting DN values of Chlorophyll-a (Chl-a) zonal statistics from Aqua-MODIS satellite imagery for the coastal waters of Visakhapatnam, Bay of Bengal, spanning January to December 2024, using buffer zones of 50km, 75km, 100km, 125km, 150km and 200km radii from the Visakhapatnam fishing harbor. This analysis revealed high consistency between the two tools, with absolute errors ranging from 0.000027 to 0.002961 mg m⁻³ and Absolute Percentage Errors (APE) ranging from 0.000001 to 0.120614. The errors were negligible up to 150 km but increased slightly at the 200 km buffer due to a recurring one-pixel discrepancy. Both tools proved reliable for delineating potential fishing zones, with errors well below ecologically significant thresholds. SeaDAS, an open-source tool, excelled in the precise processing of Net CDF data, while ArcGIS, which required format conversion to Geo TIFF, offered superior geospatial visualization and multilayer analysis.