PACE (Plankton, Aerosol, Cloud, ocean Ecosystem): Preliminary analysis of the consistency of remote sensing reflectance product over aquatic systems

NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) is a satellite mission launched in February 2024, featuring the hyperspectral Ocean Color Instrument (OCI). One of the key products released to the scientific community from PACE is spectral remote sensing reflectance (R rs (λ)). R rs (λ) is critical for estimating bio-optical and biogeochemical properties in aquatic systems, particularly concerning the presence of algal pigments, suspended particulate matter, and colored dissolved organic matter. PACE-OCI’s hyperspectral capabilities address the limitations of prior sensors, providing enhanced spectral discrimination for these properties, especially in optically complex waters. The provisional PACE-OCI R rs product is especially crucial for generating global aquatic products and supporting multifaceted research in ocean and coastal systems, which has generated significant interest in understanding its quality and potential applications. This study provides a preliminary validation of the provisional PACE-OCI R rs product (V3.1) using 15 globally distributed AERONET-OC (Aerosol Robotic Network-Ocean Color) stations. A total of 895 match-up observations between PACE-OCI and AERONET-OC (March 2024 to September 2025) were analyzed across eight wavelengths (400 – 667 nm) and 20 distinct optical water types. Results indicate overall consistency of PACE-OCI R rs , with a median symmetric accuracy ( ε ) of approximately 22.6 % and a symmetric signed percentage bias ( β ) of + 6.5 %. For clear waters, the product performed well at wavelengths between 400 – 560 nm (average ε of 17.2 %) and achieved the best accuracy at longer wavelengths (490 – 667 nm) for waters with moderate to high optical complexity (average ε of 16.3 %). However, these spectral distortions were more pronounced in waters with high optical complexity compared to those with low or moderate optical complexity. These findings highlight the quality of PACE-OCI’s provisional product to support aquatic applications and bring insights for future improvements of this R rs (λ) product.