Reconstruction of VIIRS 375 m Resolution Data for Algal Bloom Detection

The Visible Infrared Imaging Radiometer Suite (VIIRS) is fundamentally constrained by a 750 m spatial resolution in its multispectral channels, limiting its capacity for algal bloom observations. This study proposed a Spatial Residual Correlation Method (SRCM) to reconstruct 375 m VIIRS ocean color products using the 375 m I1 band (638 nm). This method is based on the scale-invariance assumption that the linear relationships (k(λ)) between spatial residuals between M-bands and I1 band are almost identical at 375 m and 750 m, and calculates a scene-specific k(λ) to derive 375 m spatial residuals of M-bands from those of the I1 band. The reconstructed 375 m remote sensing reflectance (Rrs) and chlorophyll-a (Chl-a) images show additional spatial variation compared with the native 750 m products. The ratios of reconstructed to native products are 1.001 ± 0.029 for Rrs(443) and 0.997 ± 0.032 for Chl-a, indicating consistency with the native 750 m products. The 375 m ratio of algal bloom (RAB) maps show finer spatial patterns for reported algal bloom events in the tested coastal waters. These results suggest that SRCM may be useful for algal bloom detection in the tested coastal waters, while further comparisons with independent imagery at higher spatial resolution would allow the accuracy of the added features to be assessed.