0283c3e4-2164-4dfb-a066-0c49b816d7b6 eng utf8 dataset dataset NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom polardatacentre@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact 2025-05-27 ISO 19115 Geographic Information - Metadata ISO 19115:2003(E) European Petroleum Survey Group (EPSG) Geodetic Parameter Registry 2008-11-12 publication European Petroleum Survey Group EPSGadministrator@iogp.org https://www.epsg-registry.org/ EPSG Geodetic Parameter Dataset The EPSG Geodetic Parameter Dataset is a structured dataset of Coordinate Reference Systems and Coordinate Transformations, accessible through this online registry. information publisher urn:ogc:def:crs:EPSG::3031 6.18.3 Seasonal sea ice concentration at Signy Island, South Orkney Islands, 1982-2024 2025-05-27 creation 2025-05-27 revision 2025-05-27 publication 2025-05-27 released 1.0 https://doi.org/10.5285/0283c3e4-2164-4dfb-a066-0c49b816d7b6 doi GB/NERC/BAS/PDC/02065 https://data.bas.ac.uk/ Please cite this item as: Forcada, J., Dunn, M., & Waluda, C. (2025). Seasonal sea ice concentration at Signy Island, South Orkney Islands, 1982-2024 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/0283c3e4-2164-4dfb-a066-0c49b816d7b6 This dataset comprises covariables describing the seasonal sea ice cycle around Signy Island, South Orkney Islands between 1982 and 2024. The data are derived from satellite images using R-scripts which have been made available on Zenodo. Sea ice concentration was derived from satellite measurements of percent sea ice concentration. The satellite sea ice concentration data are modelled to provide derived covariates that together measure inter-annual differences in the sea ice season. The derived covariates are: 1) day of advance: first day when sea ice concentration exceeded 15% for at least five consecutive days; 2) day of retreat: first day when sea ice concentration remained less than 15% until the end of period; 3) ice season duration: total number of sea-ice days, between day of advance and retreat; 4) sea-ice persistence: percent time sea ice was present between day of advance and retreat; 5) day of minimum sea ice extent; 6) day of maximum extent; 7) day of minimum sea ice area; 8) day of maximum sea ice area; 9) minimum area of the ocean in km2 with at least 15% sea ice concentration; and 10) maximum area of the ocean with at least 15% sea ice concentration. Sea ice covariates are used as predictors of population dynamics of Antarctic seals at Signy Island, South Orkney Islands. This work was funded by Natural Environment Research Council (UK) core funding to the British Antarctic Survey. No credit. completed Forcada, Jaume British Antarctic Survey Researcher author Dunn, Michael British Antarctic Survey Researcher author Waluda, Claire British Antarctic Survey Researcher author NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information pointOfContact asNeeded completed EARTH SCIENCE > Cryosphere > Sea Ice > Ice Extent theme Global Change Master Directory (GCMD) Science Keywords 2026-01-27 publication 23 Global Change Data Center, Science and Exploration Directorate, Goddard Space Flight Center (GSFC) National Aeronautics and Space Administration (NASA) Greenbelt MD United States of America https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords Global Change Master Directory (GCMD) Keywords The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. information publisher Advance Ice days Persistence Retreat Sea-ice concentration Sea-ice cycle theme Signy Island South Orkney Islands place Oceanographic geographical features theme GEMET - INSPIRE themes, version 1.0 2021-01-06 revision otherRestrictions no limitations to public access otherRestrictions no limitations license Open Government Licence v3.0 otherRestrictions This data is governed by the NERC Data Policy: https://www.ukri.org/who-we-are/nerc/our-policies-and-standards/nerc-data-policy/ otherRestrictions and supplied under Open Government Licence v.3 (). url url crossReference textTable eng utf8 environment -46.875 -46.875 -61.875 -61.875 1982-01-01 2024-03-31 It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk. NERC EDS UK Polar Data Centre +44 (0)1223 221400 British Antarctic Survey, High Cross, Madingley Road Cambridge Cambridgeshire CB3 0ET United Kingdom PDCServiceDesk@bas.ac.uk https://www.bas.ac.uk/team/business-teams/information-services/uk-polar-data-centre/ information distributor bytes 1 http://ramadda.data.bas.ac.uk/repository/entry/show?entryid=0283c3e4-2164-4dfb-a066-0c49b816d7b6 WWW:LINK-1.0-http--link Get Data Download data download dataset Methodology: Seasonal covariates describing the timing of the seasonal sea ice cycle and annual sea ice extent and area in relation with inter-annual variation in the sea ice edge, as estimated by a 15% sea ice concentration threshold. Sea ice concentration was derived from satellite measurements of percent sea ice concentration between 1982 and 2024, from the NOAA/NESDIS/NCEI Daily Optimum Interpolation Sea Surface Temperature (SST), version 2.1, dataset (DOISST v2.1). Selected daily data has a resolution of 1/4 degrees, from a polygon of longitude range [-44 degrees,-47 degrees], latitude range [-60 degrees,-62 degrees], and total area of 37,966km2, with the South Orkney Islands at approximately -46.875 degrees and -61.875 degrees (dataset ncdcOisst21Agg_LonPM180 URL: https://coastwatch.pfeg.noaa.gov/erddap/). The raw data consisted of sea ice concentration (from 0 to 100%) which was the relative amount of a grid cell of 1/4° covered by ice. For a larger area it was calculated as the sum of the area of each cell multiplied by the fractional concentration for that cell. Sea ice extent defined a region as either ice-covered or uncovered as a binary term; a grid cell had ice (1) or no ice (0), as defined by the 15% concentration threshold. For each year from 1982 to 2024, we considered an annual period starting approximately around the date of mean sea ice extent minimum on February 16th; i.e., day 46 in year 1 to day 410 -or 411 in leap years- of year 2. We then calculated the timing of the seasonal sea ice cycle and annual sea ice extent and area. The derived covariates were: 1) day of advance: first day when sea ice concentration exceeded 15% for at least five consecutive days; 2) day of retreat: first day when sea ice concentration remained < 15% until the end of period; 3) ice season duration: total number of sea-ice days, between day of advance and retreat; 4) sea-ice persistence: percent time sea ice was present between day of advance and retreat; 5) day of minimum sea ice extent; 6) day of maximum extent; 7) day of minimum sea ice area; 8) day of maximum sea ice area; 9) minimum area of the ocean in km2 with at least 15% sea ice concentration; and 10) maximum area of the ocean with at least 15% sea ice concentration. If the sea ice concentration never decreased below this threshold, the days of advance and retreat were set to the lower and upper limits, respectively. The R scripts used to derive this data can be found at: www.doi.org/10.5281/zenodo.15544181 Data collection: x1 .csv Data quality: Data quality control is guaranteed by the satellite data providers, NOAA/NESDIS/NCEI; and the quality of the derived covariates used in the analysis responds to the peer review process of the associated manuscript, where the data was used. For further quality control purposes, the code used to download the raw data and analysis can be found at: www.doi.org/10.5281/zenodo.15544181. asNeeded completed