Exploring The Use Of SAR Remote Sensing To Detect Microplastics Pollution In The Oceans

• Main Authors: Davaasuren, Narangerel, Marino, Armando, Boardman, Carl, Ackermann, Nicolas, Alparone, Matteo, Nunziata, Ferdinando
• Format: Conference Object
• Language: unknown
• Published: 2018
• Subjects: Pacific; North Atlantic
• Online Access: https://oro.open.ac.uk/55224/; https://oro.open.ac.uk/55224/1/seasar2018_narangerel_davaasuren.pdf

The increase in plastic pollution is advancing micro level pollution and the total weight of microplastics (<0.33mm-1.00 mm) in the ocean column. The amount of plastic in the North Pacific is estimated as 21 x 10 8 tons and in the North Atlantic as 10.4 x 10 8 tons. The plastic in marine environment will eventually degrade and it will be promptly colonized by bacteria releasing surfactants. Such surfactants will have the effect of damping the capillary and small gravitational waves on the ocean surface. Since SAR is sensitive to roughness induced by capillary waves, it may be exploited to detect bacterial activities related to plastic pollution. In this work we used Sentinel-1A and COSMO SkyMed radar images acquired in the Atlantic and Pacific gyres to detect surfactants that may be associated to plastic pollution. We are using SAR, because the damping properties of surfactants produce dark areas in images. Since area of low backscattering in SAR images could also be produced by other oceanographic/meteorological event, we exploited geophysical remote sensing products associated to time and locations synchronised to SAR acquisitions. Among other products we considered sea surface temperature, surface wind, chlorophyll, surface reflectance, turbidity and wave heights. Additionally we made sure that the areas were not within busy shipping routes. The result of the analysis is that, including effects due to colocation errors of SAR and meteorological data, we could identify a large amount of linear slicks in SAR images that were not directly related to apparent meteorological conditions. Such slicks in the gyres have the appearance of oil slicks, however in some areas they are in large amount and they are not connected to large ship traffic. At the moment these slicks seems to only be visible when the wind conditions are moderate (e.g. 6m/s) as it happen for ordinary oil slicks. Besides the work on radar data, we are making controlled experiments with micro-plastic pollution in sea water, to understand the ...