This dataset contains raw beaching data computed by marine debris simulations (run using OceanParcels) for a range of physical scenarios (surface currents from GLORYS12V1 (https://doi.org/10.3389/feart.2021.698876), Stokes drift from WAVERYS (https://doi.org/10.1007/s10236-020-01433-w), and surface winds from ERA5 (https://doi.org/10.1002/qj.3803)), as described in the accompanying manuscript. Through postprocessing, debris ‘connectivity’ matrices can be computed, providing predictions for the main terrestrial and marine source regions of plastic debris accumulating at remote islands in the western Indian Ocean. These simulations include beaching and sinking processes, and a set of example matrices is provided here (https://doi.org/10.5287/bodleian:DEdqwXZQw). However, these matrices can be recomputed for different sinking and beaching rates using the scripts archived here (https://doi.org/10.5281/zenodo.7351695), or see here (https://github.com/nvogtvincent/WIO_Marine_Debris/) for the live version with documentation. These predictions will be useful for environmental practitioners in the western Indian Ocean to assess source regions for marine debris accumulating at islands of interest, and when this debris is likely to beach. The data were produced as part of the Marine Dispersal and Retention in the Western Indian Ocean project funded by the Natural Environment Research Council (NERC) grant NE/S007474/1. See linked online references on this record for cited items given above.

The Penlee Point Atmospheric Observatory (PPAO) was established by the Plymouth Marine Laboratory in May 2014 for long term observations of ocean-atmosphere interaction. The observatory is only a few tens of metres away from the water edge and 11m above mean sea level. This dataset contains air temperature, dew point, wind speed and direction, rainfall, sulphur dioxide, ozone, carbon dioxide and methane measurements from Penlee Point Atmospheric Observatory from 2014-2017. At the mouth of the Plymouth Sound, the site (50° 19.08' N, 4° 11.35' W) is exposed to marine air when the wind comes from 110° - 240°. Typical southwesterly winds tend to bring relatively clean background Atlantic air. In contrast, winds from the southeast are often contaminated by exhaust plumes from passing ships. The PPAO is in close proximity to marine sampling stations that form the Western Channel Observatory, enabling better understanding of the ocean-atmosphere coupling.

The Penlee Point Atmospheric Observatory (PPAO) was established by the Plymouth Marine Laboratory in May 2014 for long term observations of ocean-atmosphere interaction. The observatory is only a few tens of metres away from the water edge and 11m above mean sea level. This dataset collection contains air temperature, dew point, wind speed and direction, rainfall, sulphur dioxide, ozone, carbon dioxide and methane measurements from Penlee Point Atmospheric Observatory from 2014-2017. At the mouth of the Plymouth Sound, the site (50° 19.08' N, 4° 11.35' W) is exposed to marine air when the wind comes from 110° - 240°. Typical southwesterly winds tend to bring relatively clean background Atlantic air. In contrast, winds from the southeast are often contaminated by exhaust plumes from passing ships. The PPAO is in close proximity to marine sampling stations that form the Western Channel Observatory, enabling better understanding of the ocean-atmosphere coupling.