Between 6 and 17 June 2021 a ship-mounted LIF LiDAR ran continuously along a northbound transit through the western Baltic, across the North Sea, up the Norwegian Sea and into the Barents and White seas. The four legs together hold close to 900,000 returns, making the campaign a natural cross-section of north European water types measured by one sensor under uniform calibration.
The optical contrast along the route is large: surface chlorophyll near 0.5 µg/L in the productive western Baltic, falling below 0.1 µg/L in the oligotrophic Atlantic water entering the Norwegian Sea, then rising again on the river-charged Barents and White Sea shelves. Continuous transects of this kind, one platform, one method, many regimes, are the substrate for building and checking the regional retrieval models that ocean-colour cal/val depends on.



