DOI: 10.5281/zenodo.11045944
title: Mediterranean Sentinel-2 Litter Windrows Catalogue (Jun. 2015 - Sept. 2021) v1.0

description: This dataset contains the 14,374 Litter Windrows detections found using multispectral Copernicus Sentinel-2/MSI L1c data in the Mediterranean Sea for the period June 2015–September 2021. The dataset includes exclusively the filaments deemed as valid by the research team and used in the main research of the associated research paper. The following information is provided:



Geocentric lat/lon coordinates (WGS84) of the 'centroid' position for the filament

(X, Y) coordinates of the filament's centroid related to the multispectral Sentinel-2 image array, when considering all spectral bands resampled at 10m spatial resolution.

Number of 10x10m pixels composing the filaments where floating matter has been identified.

(X, Y) coordinates for all the detected pixels within the filament and related to the associated Sentinel-2 L1c image at 10m resolution.

Original full spectrum (13 bands) for each of the pixels within the filament.

Limits of the bounding box (in image (x, y) coordinates at 10m resolution) contain the entire filament.

Full name of the Sentinel-2 L1c product containing the filament.

Central decimal time (UTC) of the associated Sentinel-2 acquisition.


The file has netcdf-4 format (NETCDF-CLASSIC), with a size of 2 GB. Note that to maintain structure, the variables related to each pixel in the filament have a size equal to the largest filament in the database. As most filaments are shorter, these variables are padded with dummie values (-999) in all the relevant fields.

ncdump will yield the following information:

netcdf file:/C:/Users/mab_l/Downloads/Science/WASP/WASP_LW_SENT2_MED_L1C_B_201506_202109_10m_6y_NRT_v1.0.nc {
  dimensions:
    n_filaments = 14374;
    box_dims = 4;
    n_max_pixels_fil = 2563;
    n_bands = 13;
    nchar = 65;
  variables:
    char s2_product(n_filaments=14374, nchar=65);
      :long_name = "Copernicus Sentinel-2/MSI L1c product";
      :description = "Full name of the Sentinel-2 product where the filament was found.";

    double dec_time(n_filaments=14374);
      :description = "Decimal time of the Sentinel-2 acquisition where the filament was found.";
      :long_name = "Decimal Time";
      :units = "year";
      :calendar = "gregorian";
      :_FillValue = -999.0; // double

    short x_centroid(n_filaments=14374);
      :units = "X image coordinate";
      :description = "X-axis position of the filament in the S-2/MSI data array at 10m resolution.";
      :_FillValue = -999S; // short
      :long_name = "X-axis centroid position";

    short y_centroid(n_filaments=14374);
      :description = "Y-axis position of the filament in the S-2/MSI data array at 10m resolution.";
      :_FillValue = -999S; // short
      :long_name = "Y-axis centroid position";
      :units = "Y image coordinate";

    double lat_centroid(n_filaments=14374);
      :units = "degrees North";
      :axis = "Y";
      :description = "Geocentric longitudinal coordinates of the filament (WGS84).";
      :long_name = "Latitude";
      :_FillValue = -999.0; // double

    double lon_centroid(n_filaments=14374);
      :long_name = "Longitude";
      :units = "degrees East";
      :axis = "X";
      :_FillValue = -999.0; // double

    int n_pixels_fil(n_filaments=14374);
      :units = "none";
      :description = "Number of detected pixels composing the filament.";
      :long_name = "Number of pixels in filament";
      :_FillValue = -999; // int

    short limits(n_filaments=14374, box_dims=4);
      :description = "Image coordinates of the bounding box containing the filament [x_lower, y_lower, x_upper, y_upper]";
      :coordinates = "n_filaments box_dims";
      :units = "(X, Y) image coordinates";
      :_FillValue = -999S; // short

    short pixel_x(n_filaments=14374, n_max_pixels_fil=2563);
      :units = "X image coordinate";
      :coordinates = "n_filaments n_max_pixels_fil";
      :description = "X-axis position of the pixels composing the filament in the S-2/MSI data array at 10m resolution.";
      :long_name = "Pixel x-axis coordinate";
      :_FillValue = -999S; // short

    short pixel_y(n_filaments=14374, n_max_pixels_fil=2563);
      :description = "Y-axis position of the pixels composing the filament in the S-2/MSI data array at 10m resolution.";
      :units = "Y image coordinate";
      :coordinates = "n_filaments n_max_pixels_fil";
      :long_name = "Pixel y-axis coordinate";
      :_FillValue = -999S; // short

    float pixel_spec(n_filaments=14374, n_max_pixels_fil=2563, n_bands=13);
      :units = "reflectance";
      :coordinates = "n_filaments n_max_pixels_fil n_bands";
      :description = "Spectral L1c (TOA) reflectance values for pixel and band on the filament.";
      :long_name = "Pixel Spectra";
      :_FillValue = -999.0f; // float

  // global attributes:
  :title = "Mediterranean Sentinel-2 Litter Windrows Catalogue (Jun. 2015 - Sept. 2021) v1.0";
  :institution = "Barcelona Expert Center (BEC), ICM-CSIC, Barcelona, Spain";
  :url = "http://bec.icm.csic.es";
  :email = "m.arias@icm.csic.es m.arias@zenithalblue.com";
  :copyright = "BEC research products are freely distributed. If these data are used for publication, please \ncite the original research work.";
  :reference = "https://doi.org/10.5281/zenodo.11045944";
  :project = "Mapping Windrows as Proxies for Marine Litter Monitoring from Space (WASP)";
  :funding = "ESA contract no. 4000130627, within the Discovery Element of the ESA\'s Basic Activities.";
  :sensor = "Multi Spectral Instrument (MSI)";
  :platform = "Copernicus Sentinel-2A/B";
  :license = "This product is distributed under Creative Commons Attribution license (CC BY 4.0).\nYou are free to share and adapt this product under the following terms:You must give appropriate credit (see copyright), \nprovide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in \nany way that suggests the licensor endorses you or your use.";
  :license_url = "https://creativecommons.org/licenses/by/4.0/";
  :Conventions = "CF-1.6";
  :time_coverage_start = "20150601T00:00:00";
  :time_coverage_end = "20210917T23:59:59";
  :geospatial_lat_min = 29.905254805021364; // double
  :geospatial_lat_max = 45.740728823657236; // double
  :geospatial_lat_units = "degrees north";
  :geospatial_lon_min = -6.703167546213006; // double
  :geospatial_lon_max = 36.20086905862957; // double
  :geospatial_lon_units = "degrees east";
  :spectral_bands = "B01, B02, B03, B04, B05, B06, B07, B08, B8A, B09, B10, B11, B12";
}

Please, if you use this dataset, make reference to it in your work: https://doi.org/10.5281/zenodo.11045944Additionally, please, refer to the original research paper (Cózar & Arias et al. (2024) 'Proof of concept for a new sensor to monitor marine litter from space', in Nature Communications)

To contact authors about this dataset, please write to M. Arias (m.arias@zenithalblue.com, m.arias@icm.csic.es) and A. Cózar (andres.cozar@uca.es).