Cross-Satellite Atmospheric Correction for Consistent Remote Sensing Reflectance from Multiple Ocean Color Satellites: Concept and Demonstrations

Abstract

Consistent bio-optical properties across multiple ocean color satellites are the key prerequisite to merging products from these satellites, thereby enhancing spatial coverage and extending temporal spans. However, due to factors such as sensor specifics and separate data processing algorithms, bio-optical properties (e.g., remote sensing reflectance, Rrs) from different ocean color missions exhibit varying discrepancies in oceanic, coastal, and inland waters. Here, we introduce a cross-satellite atmospheric correction (CSAC) scheme, which could greatly improve the consistency of Rrs products between MODIS-Aqua and other satellite ocean color missions. Specifically, using an inclusive high-quality Rrs dataset of oceanic waters obtained from MODIS-Aqua as the reference, and as an example, top-of-atmosphere reflectance from SeaWiFS (Sea-Viewing Wide Field-of-View Sensor) is directly processed to MODIS-Aqua-equivalent Rrs (RrsMA−eqv) via CSAC. As a demonstration, for independent space-time matched measurements between MODIS-Aqua and SeaWiFS, the mean absolute percent difference (MAPD) between RrsMA−eqv and MODIS-Aqua Rrs ranges from 5.9% to 22.2% across wavelengths from 412 to 667 nm. In contrast, the MAPD values between the NASA standard SeaWiFS and MODIS-Aqua Rrs products range from 10.1% to 55.1% for the same spectral bands. These results highlight the potential of CSAC in obtaining consistent Rrs products and, subsequently, Rrs-derived bio-optical properties, from various ocean color satellites, facilitating extensive and long-term ocean color observations of the global ocean.