Part of the Aquatic Ecosystem Analysis Bachelor Programme, European students gathered online from four different countries, to learn about Remote Sensing for Water Quality Monitoring over the Guadiana River catchment, a cross-border resource between Portugal and Spain, using Copernicus Sentinel-2 data.

The collaboration between The Polytechnic Institute of Beja, Portugal, and AERES University, the Netherlands, is at its fifth edition of the Integrated Project on International Aquatic Ecosystem Analysis events, focusing once more on Hyperspectral Imaging (HSI) and Multispectral Imaging (MSI) for monitoring water quality of inland waters.

This year, 19 students from the Netherlands, Portugal, Croatia and Belgium participated in the four week online programme.

Last year, the organisers introduced the use of satellite imagery for water quality monitoring, using data from the Sentinel-2 satellites of the European Union's Copernicus Programme. The idea was to provide students with a new tool to monitor harmful algae blooms using these data products, and the EO-Browser for custom script processing.

Since the programme had been a success, the format was carried on this year, adapting it to the necessary pandemic restrictions. The organisers had a full eLearning model implemented with a learning management system (LMS) to conduct lectures, tutorial sessions, seminars, work groups and the sharing of documents to enable remote collaborative work.

This was a very natural and user-friendly approach for all participants, since experts were already teaching/learning online, and all the resources that students needed to use were also web based.

Moreover, as in previous in-person editions, the students were still grouped in working teams, so the online remote environment worked well. The students developed new competences such as time management, communication and team management—the kind of soft skills that are increasingly important in the digital age.

Since this school also aims to develop intercultural competences, nationalities are purposefully mixed when creating the teams.

In terms of training, the students have a set of four workshops during the first week, to get acquainted with the subject:

• Remote Sensing for Water Quality Monitoring
• HSI Principles and Applications
• Copernicus Sentinel-2 Product Processing for Water Quality Monitoring: Introduction to Copernicus Open Access Hub & EO Browser
• Copernicus Sentinel-2 Products for Water Quality Monitoring: Spectral Indices & Water Quality Parameters

During these workshops, the students firstly were familiarised with remote sensing concepts and practical applications. The use of specific Copernicus Sentinel-2 spectral bands was then introduced, linking the bands wavelength to the spectral fingerprint of materials in order to detect specific features (e.g. chlorophyll, bare soil). Lastly, the use of spectral indices and empirical models (calibrated with in situ measurements) to map relevant water quality parameters were addressed.

With these tools, the students had to find the appropriate bands, indices and models to diagnose the water quality in the river, present mitigation measures, and the definition of a satellite image-based early warning system, for events such as harmful algae blooms.

Comprising a constellation of two polar-orbiting satellites placed in the same sun-synchronous orbit, the Copernicus Sentinel-2 mission aims at monitoring variability in land surface conditions. Its wide swath width (290 km) and high revisit time (10 days at the equator with one satellite, and 5 days with 2 satellites under cloud-free conditions, which results in 2-3 days at mid-latitudes), supports monitoring of Earth's surface changes.

Upon completion of the workshops, students started to observe the region, which this year was the entire Guadiana River catchment, to identify problems and to select a particular area of study.

During the other three weeks, the students attended various seminars on different topics (ecology, water quality, environmental impact assessment methodologies), held by specialists from Brazil, Poland, Portugal, Croatia and the Netherlands.

As in last year's course, the Portuguese Space Agency (PTSpace) carried out an excellent seminar on the Copernicus Programme. The idea was to give students an overview of the programme and the lines of action, reminding students of the benefits of a free and open resource such as Copernicus.

At the end of the four week programme, students presented the full project to the other teams:

• How and where they identified problems of the river catchment using Copernicus Sentinel-2 data
• Possible causes of the problems
• Proposed solutions and an environmental impact analysis (also considering the relevant stakeholders and ecological key factors)
• Definition of an early warning system, owing to the Copernicus Sentinel-2 images

See examples of other time lapses produced by the teams:

• Time lapses of cyanobacteria on the Guadiana River
• Time lapses of NDWI and cyanobacteria distribution maps in the Guadiana River

Dr Nuno Pereira, Professor at the Polytechnic Institute of Beja, states, "We ended this year's edition with the feeling of "mission accomplished". The projects presented by the teams were very good and students showed to have acquired new competences in remote sensing and satellite image processing, which will undoubtedly be very useful for their future professional lives. We are looking forward to the 2022 edition, using a blended learning format."

About the Copernicus Sentinels

The Copernicus Sentinels are a fleet of dedicated EU-owned satellites, designed to deliver the wealth of data and imagery that are central to the European Union's Copernicus environmental programme.

The European Commission leads and coordinates this programme, to improve the management of the environment, safeguarding lives every day. ESA is in charge of the space component, responsible for developing the family of Copernicus Sentinel satellites on behalf of the European Union and ensuring the flow of data for the Copernicus services, while the operations of the Copernicus Sentinels have been entrusted to ESA and EUMETSAT.

Did you know that?

Earth observation data from the Copernicus Sentinel satellites are fed into the Copernicus Services. First launched in 2012 with the Land Monitoring and Emergency Management services, these services provide free and open support, in six different thematic areas.

Acknowledgements

The International School Organising Commission includes: Fátima Carvalho (Coord.), Nuno Pereira, Fernanda Pereira, Anabela Durão, Polytechnic Institute of Beja – Portugal and Annet Pouw (Coord.), Floris Keiser, AERES University of Applied Sciences Almere – the Netherlands