Recent advances in geostationary satellites for inland and coastal aquatic systems: scientific research and applications.

Inland and coastal environments are complex ecosystems composed of suspended and dissolved materials, affecting light propagation within the water column. Satellite-based water quality research relies on water optical properties provided by optical sensors on board of polar orbit satellites since the 1980's. Specifically, Geostationary (GEO) ocean colour satellites offer high temporal resolution (e.g. every 15-minute observations), moderate spatial resolution (0.5–1 km) at regional scale, making them a promising alternative to polar orbiting satellites for near-continuous monitoring of highly dynamic aquatic ecosystems. This literature review examines the evolution of geostationary satellite technology and its applications in monitoring inland and coastal waters. A summary of the most relevant studies using geostationary sensors is provided for key water quality indicators such as chlorophyll-a and algal organisms, total suspended solids, and turbidity. Also, geostationary missions were well-detailed, with their available sensors and characteristics. Although this research topic is still incipient, recent studies have demonstrated the potential of GEO multi-spectral observations in understanding sub-daily water quality patterns. Notably, most research studies have focused on Asia, suggesting unexplored opportunities globally. Advanced Himawari Imager (AHI) and Geostationary Ocean Colour Imager (GOCI) have been used to improve water quality estimates, and inherent challenges were documented, such as algorithm validation, limited spatial resolution, and high volume of images and auxiliary files to be managed. The opportunities for new studies range from algorithm development for atmospheric correction, cloud masking, and bidirectional reflectance corrections to inter-comparison with existing sun-synchronous satellites. Geostationary satellites are promising avenues for future research on near-continuous monitoring of inland and coastal water resources. [ABSTRACT FROM AUTHOR]