High-resolution water optical properties in Lake Geneva


Thetis profiler (right) surfaces near the platform LéXPLORE (left) in Lake Geneva. Every 3 hours, it scans the water optical properties over the top 50 m and sends automatically the data to our servers. Its operation is unique in inland freshwater.

We use water optical properties as proxies to characterize physical and biogeochemical processes in lakes. Since October 2018, the sophisticated Thetis autonomous profiler is deployed near the LéXPLORE Platform, and scans the water column over the top 50 m every 3 hours, with a 10 cm vertical resolution. The profiler measures optical properties and water parameters.
Each time the Thetis reaches the surface, data is sent automatically to our servers. Then, the data is analysed extensively with a focus on spatio-temporal heterogeneities of primary production in large lakes. Our data serves also as reference for in situ measurements to validate numerical modelling approaches (link to https://www.eawag.ch/en/department/siam/projects/datalakes/), and calibrate remote sensing observations.(Camille Minaudo, Daniel Odermatt)