RESEARCH
Plastic Litter Project 2020
Plastic Litter Project (PLP) has a new dedicated site. Please redirect to:
http://plp.aegean.gr/
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. Please redirect to our new dedicated webpage: http://plp.aegean.gr/.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.
PLP 2020 Experiment Log
22/10/2020. Our sixth and last test deployment day with marine litter.
The sixth experiment day was conducted successfully. All 12 targets and anchors were deployed as planned. Weather conditions were optimal, some clouds during the early morning which had cleared up completely before data acquisition. High humidity and aerosol concentrations however could have produced signal interference. The sea state was calm, with winds not exceeding 2 Bf. PRISMA and WV II satellite data were acquired. Additionally, UAV optical and hyperspectral data were acquired using the DJI Phantom 4 Pro and S1000 drones.
14/10/2020. Our fifth test deployment day with marine litter.
The fifth experiment day went on as planned. All 12 anchors and targets were deployed successfully. Wind and wave conditions were good, with wind speeds in the range of blah and low waves. The sky was partly cloudy throughout the morning. During satellite acquisition a cloud formation overshadowed the deployment site and as a result no useable satellite data were acquired. UAV multispectral, thermal and optical data were successfully acquired. In addition to the 12 targets, a large 28 m diameter circular target with a single row of HDPE mesh was deployed. Four lines of rope spanning the diameter of the ring were used in an effort to restrain the ring from taking an elliptical shape. The test deployment was performed in order to assess a series of parameters such as maneuverability inside and outside of the water, buoyancy, shape retention, robustness. Due to the flexibility of the HDPE pipe used, the ring took an elongated shape during towing in the water, which tended to transition back into a circle after the towing stopped. When the ring was not tensioned into a circular shape, the non-floating ropes sank and got entangled in rocks in the shallows, hampering movement of the target. In an actual deployment the HDPE mesh would cover the entirety of the target surface, and in addition to the ropes, would aid to avoid the elongation of the ring. However, the anchoring that will be used for deployment will have to guaranty that the ring is restricted from large deformations. In terms of durability, in spite of the large deformations and forces during maneuvering and towing, the compression fittings held with no issues. A team of at least 10 to 12 people is considered necessary in order to effectively maneuver the ring on land.
18/09/2020. Our fourth test deployment day with marine litter.
On Friday 18/9/2020 it was the first deployment of the targets constructed in collaboration with NTUA. 12 targets were successfully deployed using the 12 anchors previously set. PRISMA hyperspectral and UAS optical, multispectral and hyperspectral data were acquired. Conditions were optimal, although the optical depth of the atmosphere was limited due to high water vapour concentrations. During target deployment, the boat team detected a number of PET water bottles and other marine litter items. The PET bottle targets were inspected by the team in order to exclude the possibility of contamination due to target damage. The team collected a total of about 20 PET bottles floating towards Tsamakia beach (from east to west), which were also inspected. None of the collected bottles had the characteristic holes used to fasten the bottles to the target frame. The origin of the high concentration of PET bottles is unknown. Other sighted items included: food wrappings, single use face masks and EPS foam items.
06/07/2020. Our third test deployment day with marine litter.
On Monday 06/07/2020 it was the 4th test deployment for PLP2020. The mesh target performed well with no issues; additional 4L containers used to raise the mesh, but most of the target surface was still slightly submerged. The “sandwich”-type target performed better without the intermeshed lines, however the net was slightly damaged, with no loss of litter to the environment. The specific net type is not applicable and a thicker net with a tighter mesh will be tested.
01/07/2020. Our second test deployment day with marine litter.
On Wednesday 01/07/2020 it was the 3rd test deployment day overall for PLP2020. The mesh target performed well with no issues; additional 4L containers used to raise the mesh, but most of the target surface was still slightly submerged. The “sandwich”-type target did not perform as expected, with more intense grouping occurring than what was observed with the cage-type target. The main hypothesis is that double net structure in addition with the intertwined thin rope that was used to create “pockets” did not allow the debris to flow back with the waves in order to cover the entire target area. Both targets had good buoyancy with no additional floating devices needed.
16/06/2020. Our first test deployment day with marine litter.
On Tuesday 16/06/2020, we performed the second test deployment of the two circular targets. The mesh target was deployed in the same manner as the previous date, with additional 4 liter buoyant containers attached below the mesh in an effort to slightly raise it from the sea surface. The cage-type target was partially filled with free-floating marine litter, covering about one quarter of the target area, in order to assess whether the debris would uniformly spread along the entire area of the target or concentrate to the side of the target due to wave action. A supporting mesh was attached to the bottom of the target in order to avoid loss of material to the environment. Results suggest that a partial grouping of the materials does occur due to wave action, especially during wind gusts, however most of the debris was uniformly distributed on the target area, although towards the downwind side of the target. The testing was performed during Sentinel 2 acquisition in order to assess the visibility of the new targets and obtain spectral measurements. In addition, UAV optical images were acquired using a DJI Phantom Pro V2, mainly for visualization purposes. Conditions were optimal with a light breeze of about 3 Beaufort and low waves.
10/06/2020. Our first test deployment day.
On Wednesday 10/06/2020 we performed the first test deployment of the new 7 m diameter circular targets constructed for PLP2020. The first of the two targets was a prototype cylindrical cage-type target, much like an aquaculture structure, which did not contain any marine litter. The second target was a circular frame with a white polyethylene mesh attached on the frame structure. Both targets were deployed and anchored at sea in order to assess their robustness, ease of deployment and buoyancy. UAV optical and thermal images were captured using a DJI Phantom 4 V2Pro and a Mavic 2 Enterprise. Conditions were excellent and the test was a success.
23/05/2020. Our first volunteering act.
Our third test on detecting and validating artificial plastic targets on the sea surface using UAV and satellite images technology has just begun. On Saturday 23/5/2020, the Municipality of Mytilene and the Marine Remote Sensing Team of the Department of Marine Sciences of the University of the Aegean - joined their forces to clean the beaches in the airport area of Mytilene and collect plastics that will be used in the research program Plastic Litter Project 2020.
Stay tuned for more news about PLP 2020!
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