Marine Litter is a global problem affecting the world’s oceans. State of the art techniques are needed for the detection and quantification of floating marine plastics and remote sensing can be particularly useful for monitoring large areas. As the scientific community works towards the specification of sensors for the monitoring of marine litter, there is a direct need for marine debris indicators for the detection, classification, quantification and tracking of marine litter.

 

Detection of marine litter with remote sensing datasets is essential, and proof-of-concept studies have demonstrated the classification of the marine plastics in the laboratory and in the Great Pacific Garbage Patch using hyperspectral imaging. Remote sensing is one of the tools necessary for the detection of floating marine plastics because of the extensive area coverage and frequent observation. While floating plastics are reported in high concentrations in many places around the globe, no referencing dataset exists either for understanding the spectral behavior of plastics in the real environment, or for calibrating remote sensing algorithms and validating their results. To tackle this problem, we initiated the Plastic Litter Projects (PLP), with the objective to construct large artificial targets and to deploy them on the sea surface. The PLP’s scope is:

 

  • to explore the feasibility of detecting plastics in the aquatic environment using UAV and the open access Sentinel-2 mission,
  • to extract meaningful spectral measurements in near-real scenarios, and
  • to simulate the coarse satellite pixel using the fine UAS resolution.
 

The first PLP was conducted in 2018 (PLP2018) as an innovative exploratory application of open-access satellite imagery and unmanned aerial systems (UAS) data for the remote detection of floating marine plastics in natural waters. Three large artificial 10×10 m plastic targets were designed and constructed, matching the Sentinel-2 RGB and NIR bands spatial resolution. During the second PLP (PLP2019), 10 smaller targets were created in order to be closer to reality and to examine the limitations of the detection with Sentinel-2 images. In PLP2020 we work towards creating a reference target for the scientific community, and extending deployment duration in real conditions with the construction of semi-permanent targets.

Dr Konstantinos Topouzelis

Head of Marine Remote Sensing Group

Department of Marine Sciences, University of the Aegean