THE HOLBINA-RAZIM SYSTEM, A TESTBED FOR SENTINEL-3 SATELLITE CALIBRATION FOR DELTAIC PHYCOCYANINDOMINATED SEVERE ALGAL BLOOMS

Abstract

The Holbina–Razim lake system serves as a calibration testbed for satellite-based algal pigment analysis during severe algal blooms (SABs) in deltaic environments. We demonstrate the reliability of this environment for field-to-satellite comparisons by integrating an 8-year historical dataset with in-situ measurements from a 2026 cyanobacterial SAB. Spatial gradients of chlorophyll-a and phycocyanin were validated against Sentinel-3 Normalized Difference Chlorophyll Index (NDCI) and Phycocyanin Index (PCI) parameters. Our findings confirm that the Holbina–Razim system provides a robust, scalable framework to benchmark remote sensing algorithms for phycocyanin in highly eutrophic, deltaic waters globally.