Drones, Ships and Satellites over Lake Balaton

29 July 2019

In July 2019 the international MONOCLE research team gathered for their second validation campaign, this time at Lake Balaton in Hungary.

In July 2019 the international MONOCLE research team gathered for their second validation campaign, this time at Lake Balaton in Hungary. Hosted by the Balaton Limnological Research Institute (with major thanks to Viktor and Attila ) this campaign focussed on testing the suite of MONOCLE sensors and platforms across optical gradients in a large shallow lake. MONOCLE (an EU H2020 project) aims to lower the cost of collecting and sharing reference observations for satellite based water quality services. The project, coordinated by Plymouth Marine Laboratory, is developing highly automated methods as well as low-cost devices suitable to be operated by experts and non-experts alike.

Over a three-day campaign, coordinated by the University of Stirling, the wide range of sensors and platforms being developed in MONOCLE were put to the test at three sites across the lake. Lake Balaton is one of the largest natural lakes in Europe and is fed mainly by the river Zala. The lake is shallow throughout and suspended mineral particles form a gradient from highly turbid waters in the western basins to clearer waters in the east. Satellite images (below) taken from the Sentinel-3 satellite showed that an algal bloom developed in the west, taking up river-fed nutrients and benefiting from increasing water temperatures in the heatwave that held continental Europe in its grip at the time.  Boats were deployed to take in situ measurements that would be used to validate sensor data collected from hyperspectral reflectance radiometers integrated in the So-Rad platform (PML) and the HSP (Peak Design) to collect hyperspectral diffuse and downwelling attenuation, both mounted on a car ferry, KdUINO (kdUSTICK and KduMods by CSIC) deployed alongside weather stations in the lake and a shore-based WISPStation

Colleagues_from_Sitemark_preparing_a_consumer_drone_with_extended_payload_for_launch.jpgAt the same time VITO, Sitemark and PML flew two drones (DJI Phantom 4 pros) from either shore or boat using an RGB + Multispectral MicSense Red Edge-M camera (Sitemark) as well as a hyperspectral radiometer (PML) to collect high resolution observations to compare against the boat and shore based radiometric, optical and biogeochemical measurements.  The drones also trialled a new “press-the-button” approach to execute pre-defined flight plans optimized for collecting observations over water surfaces. Drone data were successfully processed in a (semi)-automated workflow to be used within hours after data collection.

Complimentary Citizen Science data (FWW kits, mini Secchi disk and the Hydrocolor app courtesy of advisory board member Emmanuel Boss) were gathered at all test sites throughout the campaign. Every day water samples were taken back to the laboratory for analysis of optically active water constituents such as algal pigments, suspended particles and dissolved organic matter.

The information gathered from these multiple sources was compiled and taken back to our respective laboratories for more detailed analysis and to improve automated work flows. The data collected will help to hone and further advance the sensors and water quality monitoring solutions developed in MONOCLE.

Alongside the fieldwork activities, researchers back at PML were monitoring the flow of field data from the sensors into a common ‘back-end’. This is a data infrastructure designed to flexibly let sensors systems and databases exchange observation data  so it can be combined with satellite observations and made available to researchers, consumers and agencies. The data infrastructure is designed to be as open as possible and provide opportunities for further exploration and exploitation of near real-time observations, for example:
  • Provide feedback on a measurement to a citizen scientist
  • Provide an uncertainty estimate with each measurement, identify anomalies and sensor drift
  • Provide an alert output when certain thresholds are passed / early warning
  • Support a trigger service for sensors to measure at certain times/frequencies (e.g. measuring at a satellite overpass or triggering a drone flight  for a certain monitoring request)
Take a look at our video diary to see just a few of the team’s activities at Lake Balaton.  Our next campaign will take place in Sweden in early summer 2020 focusing on Citizen Science programmes followed by a large campaign to further test our sensor network in the Danube delta in September 2020.

For full details of the project, our partners and our resources, or to sign up for project updates see monocle-h2020.eu.

Related information and links

Watch the video diary above to see more of the team at Lake Balaton

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