Satellites can help to detect plastic in the oceans1 min read
A study in Scientific Reports shows how information from satellites can be used to identify the plastic among marine debris.
According to a team of researchers from the United Kingdom and Greece, it is possible to use the eyes of the satellites that orbit the Earth to find the plastics dispersed in the planet’s waters. And hopefully, use them to plan remediation operations or as an environmental monitoring tool.
The satellite search methodology identifies a characteristic spectral signature of the material of interest in order to understand how the different materials absorb and reflect the different wavelengths.
To test their hypothesis, the researchers used optical satellite data of the ESA Sentinel-2 mission (whose maximum resolution is 10 meters by 10 meters).
First of all, the researchers developed an index that would allow them to identify piles of floating material starting from the revelations of the satellites. Subsequently, they created a sort of library of spectral signatures of different materials. But they also included in their library the signals attributable to substances that are often found mixed with plastic once at seas, such as wood, foam, or algae.
Finally, they tested their system on a series of coastal environments where it was probable to find piles of floating debris, identified thanks to the analysis of the literature combined with news on the media and posts on social media.
The areas chosen were coastal areas of Ghana, Vietnam of Scotland, or Canada, for which data captured by satellites were extrapolated.
The scientists were thus able to identify plastic patches in the areas under observation, some with characteristics typical of plastics, classified as such by an algorithm with high percentages of accuracy. Suspected plastics were successfully classified as plastics with an accuracy of 86%.