10:00 〜 10:15
[MIS17-05] Numerical Modelling on transport of riverine plastic debris released into Indian Ocean
キーワード：Marine Plastics, Particle Tracking Model, Indian Ocean
Large amounts of mismanaged plastic wastes enter the world`s oceans every year. Indian Ocean is particularly important in this regard because of the high amount of waste released from the countries bordering it coastlines. Despite this, little is known about the transport of plastic debris in the Indian Ocean. Therefore, this research aims to understand the transport of plastic debris and various factors influencing the plastic debris transport in Indian Ocean using a Particle Tracking Model (PTM).
In PTM the modelled particles were carried by ocean surface currents from HYCOM, horizontal diffusivity, Stokes drift and satellite derived winds (windage). The model incorporated an exchange process between ocean and beaches such that the modeled particles washed ashore on beaches were re-drifted on a timescale of 200 days in accordance with the field experiment of Kataoka et al., (2013). Plastic input from South Asian countries was incorporated into the model based on Lebreton et al. (2017) `s estimate. The modeling starts in the ocean free of plastics and continued for 10 years under the monthly-averaged currents and winds repeatedly used in the computation.
The PTM experiments indicated higher beaching in Indian Ocean in the Summer (south-westerly monsoon). The model showed a higher seasonality in number of beached particles in the Bay of Bengal which is consistent with the observation. The seasonality was influenced by wind and Stokes drift. Further, the tracking experiments indicated the role of wind and Stokes drift in trapping macroplastic particles in the northern hemisphere Indian Ocean.
In PTM the modelled particles were carried by ocean surface currents from HYCOM, horizontal diffusivity, Stokes drift and satellite derived winds (windage). The model incorporated an exchange process between ocean and beaches such that the modeled particles washed ashore on beaches were re-drifted on a timescale of 200 days in accordance with the field experiment of Kataoka et al., (2013). Plastic input from South Asian countries was incorporated into the model based on Lebreton et al. (2017) `s estimate. The modeling starts in the ocean free of plastics and continued for 10 years under the monthly-averaged currents and winds repeatedly used in the computation.
The PTM experiments indicated higher beaching in Indian Ocean in the Summer (south-westerly monsoon). The model showed a higher seasonality in number of beached particles in the Bay of Bengal which is consistent with the observation. The seasonality was influenced by wind and Stokes drift. Further, the tracking experiments indicated the role of wind and Stokes drift in trapping macroplastic particles in the northern hemisphere Indian Ocean.