Concentration, anisotropic and apparent colour effects on optical reflectance properties of virgin and ocean-harvested plastics.

Autor: Garaba SP; The Ocean Cleanup, Batavierenstraat 15, 3014 JH Rotterdam, The Netherlands; Marine Sensor Systems Group, Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Schleusenstraße 1, 26382 Wilhelmshaven, Germany. Electronic address: shungu.garaba@uni-oldenburg.de., Arias M; ARGANS Limited FR, 260 Route du Pin Montard - BP234, 06904 Sophia-Antipolis cedex, France., Corradi P; Optics Section, Mechatronics and Optics Division, European Space Research and Technology Centre (ESTEC), European Space Agency, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands., Harmel T; Géosciences Environnement Toulouse (GET), UMR5563, Institut de Recherche pour le Développement (IRD)/Centre National de la Recherche Scientifique (CNRS)/Université Toulouse 3, 14 Avenue Edouard Belin, 31400 Toulouse, France., de Vries R; The Ocean Cleanup, Batavierenstraat 15, 3014 JH Rotterdam, The Netherlands., Lebreton L; The Ocean Cleanup, Batavierenstraat 15, 3014 JH Rotterdam, The Netherlands; The Modelling House Limited, 3 Bay View Road, Raglan 3225, New Zealand.
Jazyk: angličtina
Zdroj: Journal of hazardous materials [J Hazard Mater] 2021 Mar 15; Vol. 406, pp. 124290. Date of Electronic Publication: 2020 Oct 16.
DOI: 10.1016/j.jhazmat.2020.124290
Abstrakt: We present reflectance measurements collected from virgin and ocean-harvested plastics. Virgin plastics included high and low density polyethylene (HDPE, LDPE), polypropylene (PP) as well as polystyrene (PS). Ocean-harvested plastics were ropes, sheets, foam, pellets and fragmented items previously trawled from the North Pacific Garbage Patch. Nadir viewing angles and plastic pixel coverage were varied to advance our understanding of how reflectance shape and magnitude can be influenced by these parameters. We also investigated the effect of apparent colour of plastics on the measured reflectance from the ultraviolet (UV - 350 nm), visible, near to shortwave infrared (NIR, SWIR - 2500 nm). Statistical analyses indicated that the spectral reflectance of the plastics was significantly correlated to the percentage pixel coverage. There was no clear relationship between the reflectance observed and the viewing nadir angle but dampened materials seemed to be more isotropic (near-Lambertian) than their dry counterparts. A loss in reflectance was also determined between dry and wet plastics. Location of absorption features was not affected by the apparent colour of objects. In general, ocean-harvested plastics shared more identical absorption features (~960, 1215, 1440, 1732, 1920 nm) and had lower reflectance intensity compared to the virgin plastics (~980 nm). Prospects for satellite retrieval of plastic type and pixel plastic coverage are discussed based on Top-of-Atmosphere (TOA) signal simulated through radiative transfer computation using the documented plastic reflectances. Non-linear relationships between TOA reflectance and plastic coverage were observed depending on wavelength and plastic type. Most of the plastics analysed impact significantly the TOA signal but two plastic types did not produce strong signal at TOA (hard fragments, LDPE). Nevertheless, all plastic types produced detectable signals when observations were simulated within the sunglint direction. The measurements collected in this study are an extension to available high quality spectral reference libraries and can support further research in developing remote sensing algorithms for marine litter.
(Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: