Department Surface Waters - Research and Management

Hyperspectral retrieval of stratification in aquatic systems

Oceans and inland waters play a major role in global biogeochemical cycles. Therefore several polar-orbiting earth observation satellites are monitoring water quality parameters by means of measuring reflected sunlight.
However, vertical variations in water quality are neglected by current retrieval methods. This causes significant errors where the euphotic depth exceeds the depth of the mixed surface layer (Nouchi et al., 2018).

As members of NASA’s Science and Applications Team for the PACE satellite mission, we investigate how to overcome this limitation. Besides hyperspectral data as available from PACE in the future, we use an automated bio-optical profiler and hydrodynamic models. The Thetis profiler is moored next to the LéXPLORE research platform and acquires detailed absorption and scattering measurements several times a day. The operational model on the Meteolakes web page was developed by EPFL and Eawag, and allows the prediction of mixed layer depths.
These unique information sources for Lake Geneva open new opportunities for hyperspectral signal interpretation. Ultimately, such an integration of models and observations will improve our understanding of aquatic processes in time and space.



Nouchi, V.; Odermatt, D.; Wüest, A.; Bouffard, D. (2018) Effects of non-uniform vertical constituent profiles on remote sensing reflectance of oligo- to mesotrophic lakes, European Journal of Remote Sensing, 51(1), 808-821, doi:10.1080/22797254.2018.1493360, Institutional Repository