Doctoral defence: Alice Fabbretto “Exploiting spaceborne imaging spectroscopy in optically complex waters for aquatic ecosystems mapping ”

On 21 January at 14:15 Alice Fabbretto will defend her doctoral thesis “Exploiting spaceborne imaging spectroscopy in optically complex waters for aquatic ecosystems mapping“ for
obtaining the degree of Doctor of Philosophy (in Environmental Technology).

Supervisors:

Associate Professor Krista Alikas, University of Tartu

PhD Claudia Giardino, National Research Council (Italy)

PhD Mariano Bresciani, National Research Council (Italy)

Opponent:

Professor Ana Belén Ruescas Orient, University of Valencia (Spain)

Summary

This thesis explores how data from the Italian space mission PRISMA, a hyperspectral satellite for Earth Observation, can be exploited to study the ecological status of lakes and coastal waters. The research focuses on validating PRISMA data and combining it with other existing similar European missions, DESIS and EnMAP, to improve the monitoring of aquatic ecosystems. Aquatic environments are vital for biodiversity, climate regulation, and human well-being, yet they face increasing threats from climate change, eutrophication and pollution. Traditional field measurements, though accurate, cannot capture large-scale or temporary phenomena. Satellite remote sensing offers a powerful, complementary way to monitor these environments continuously and globally.

Hyperspectral sensors like PRISMA records hundreds of narrow spectral bands, enabling detailed detection of water quality and aquatic vegetation. The study assessed the accuracy of PRISMA data by means of comparison with ground measurements from international observation networks and ad-hoc fieldworks.

Results showed that PRISMA performs well in key visible wavelengths, and that advanced processing methods can further improve the accuracy. Using the validated data, maps of chlorophyll-a, suspended matter, and aquatic vegetation were generated. When combined with DESIS and EnMAP, PRISMA data allowed broader and more frequent monitoring, revealing seasonal changes and trends in water quality and vegetation across Italian and Estonian lakes. The results demonstrate that spaceborne hyperspectral satellites are valuable tools for understanding and managing aquatic ecosystems. Their integration into environmental monitoring not only supports the European Water Framework Directive, but also paves the way for future missions, such as the launch of the European CHIME satellite planned for within the next five years.