Positions and dimensions of the A68 icebergs between September 2020 and April 2021 ...

• Main Authors: Smith, Roseanne, Bigg, Grant
• Format: Dataset
• Language: English
• Published: NERC EDS UK Polar Data Centre 2023
• Subjects: "EARTH SCIENCE","CRYOSPHERE","GLACIERS/ICE SHEETS","ICEBERGS"; "EARTH SCIENCE","CRYOSPHERE","SEA ICE","ICEBERGS"; "EARTH SCIENCE","OCEANS","SEA ICE","ICEBERGS"; A68; Icebergs; South Georgia; satellite observations; trajectories; Centre Point; Scotia Sea; Sheffield; Sea ice
• Online Access: https://dx.doi.org/10.5285/d56d9e3f-80d2-4076-9e70-24f662c0e362; https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01732

This dataset contains daily positions of the A68 family of giant icebergs during their drift through the Scotia Sea and South Atlantic between 2020-09-01 and 2021-04-16. Positions were obtained using optical imagery collected by MODIS Aqua and Terra satellites. For the parent iceberg A68A, the evolving dimensions (long and short axis length, area) are also provided, based on Synthetic Aperture Radar imagery acquired by Copernicus Sentinel 1A and 1B satellites. This data can be used to plot the trajectories of the A68 icebergs during their drift in the Scotia Sea and near South Georgia. This data was collected during an MSc/MRes student project at the Department of Geography, University of Sheffield, in 2020/21. The work was not supported by any funding or research grants. ... : The daily centre-point positions of the A68 icebergs, recorded as decimal degrees, were tracked using MODIS Aqua and Terra optical imagery displayed through NASA's EOSDIS Worldview tool (https://worldview.earthdata.nasa.gov/). Where cloud cover precluded accurate iceberg positioning for a single day, the coordinates were interpolated based on the positions of the preceding and subsequent days, assuming constant speed. For the parent iceberg A68A, the positions of the two ends of the iceberg's major (long) axis are also provided, to give a sense of the iceberg's evolving orientation. Lengths of A68A's major and minor axes, and area, were obtained using Synthetic Aperture Radar (SAR) data acquired by the European Space Agency (ESA) Copernicus Sentinel 1A and 1B satellites (https://scihub.copernicus.eu/). The dates and file codes of the 11 SAR images used are provided. The major axis is defined as two most distal points on the iceberg; the minor axis is 90 degrees perpendicular and at the widest point. ...