The first field deployments of our micro-sensor systems went in this week at two sites in southwestern France, Parentis Lake and Ambès on the Dordogne estuary. Each site carries an mFL-12 micro-fluorescence lidar and an mHR-2 micro-hyperspectral radiometer, four instruments in total, and both sites are now running unattended.
The two sensors read the same water by opposite means, which is the reason they are deployed as a pair. The mHR-2 is passive, and estimates water-leaving reflectance (Rrs) from a sequence of downwelling irradiance (Ed), sky radiance (Ls), and total radiance (Lt), which is the quantity an ocean-colour satellite estimates from orbit. The mFL-12 is active, and puts its own laser into the water to read the fluorescence signatures of what is dissolved and suspended in it, chlorophyll pigments and CDOM among them. One measures what the water looks like from above, the other measures what is actually in it, and the value is in holding both at the same place and the same moment.
Both sites measure twice per hour, day and night, without anyone present. That cadence is the point of the programme rather than a specification detail: the lakes, rivers, and lagoons covered by the Water Framework Directive are otherwise sampled at whatever density a person carrying a bottle can reach, which is too sparse in time to show what a discharge did or whether a policy worked.
These deployments run within OQOMETHI, funded under France 2030 and operated by ADEME, with vorteX-io coordinating the consortium and Magellium alongside. Our workpackage is the sensors. A web portal for near real-time access to the data is in development and will be opened publicly, and a third site in southern France follows in the coming weeks.