The Baltic Sea is one of the most polluted areas in the world and is especially vulnerable to environmental changes caused by climate change. With increasing requirements from EU regulations, monitoring of coastal areas is in the focus of research as ocean colour remote sensing has a high potential to improve environmental monitoring.

Advantages of satellite data are that large areas can be scanned at once, beyond country borders and monitored automatically. Oceanic remote sensing data now have accuracies similar to traditional lab measurements, but accurate retrieval of water quality parameters in coastal zones is still a challenge. Coastal zones have very heterogenic optical properties because of inflow from rivers with very diverse content, resuspension of bottom material, and high nutrient concentrations which result in algal blooms. Also correction for atmospheric effects is a complex matter for coastal areas. Therefore, dedicated locally calibrated algorithms are needed for coastal zones. Using the appropriate algorithms improves the remote sensing data in coastal zones to a great extent, and allows monitoring to be done based on this data.

Focus on the Baltic Sea

Optically, the Baltic Sea is a special case. It has much higher concentrations of humic substances than other seas, which makes the Baltic Sea rather dark. With the almost fresh water in the Gulf of Bonthnia and the inflow of saline water from the North Sea, and coastal zones ranging from steep and rocky to shallow and sandy the colour of the Baltic Sea is very diverse and exposed to very strong environmental gradients. In summer large cyanobacterial blooms tend to occur in the Baltic proper and in winter the solar angle is low and a large part of the sea is covered in ice, making remote sensing of the Baltic Sea a real challenge.

In all countries bordering the Baltic Sea, remote sensing research is carried out. Co-operation has intensified during last decade due to the Nordic Network of Aquatic Remote Sensing (NordAquaRemS) and the Nordic Network for Baltic Sea Remote Sensing (NordBaltRemS). Both networks were initiated and coordinated by Stockholm University.

During the funded network period we have tested and adapted remote sensing methods for use across the whole Baltic Sea basin. This required intense collaboration between the Baltic Sea partners, both in terms of remote sensing and validation, as well as for data management. The network has created collaboration opportunities and exchange between universities, companies and governmental agencies. The network has also supported mobility exchange of young researchers and PhD students between the partner institutes.

The network will continue organizing bio-optical and remote sensing workshops where methods and results can be discussed with scientists working on Baltic Sea remote sensing.

Curriculum development

Over the years, the Nordic network has operated as an ‘umbrella’ research school for students and young researchers in marine remote sensing. The partners with most experience in a certain topic have organized courses and workshops on specific topics. We also invited lecturers from other countries such as the UK, USA, Canada and Australia. In this way, students from all  partner institutes had the opportunity to participate in training courses with a very high standard.  

BEAM training course in Oslo, 2011