This dataset contains multiple variables with spatio-temporal information relating to sea-ice and the southern ocean. This collection of data is utilised by the nilas.org platform for dynamically visualising these variables in the web browser. Together they provide a valuable resource for understanding the interactions between physical, climate and biogeochemical parameters. These include variables to understand sea-ice in three dimensions, chlorophyll and sea surface temperature. The time range of these data covers from 1980 until the present and the spatial coverage is Antarctic circumpolar.
Name: Daily Sea Ice Concentration
Desc: Sea ice concentration is a measure of the amount of size ice over an area. It is calculated from satellite observations of sea ice for all areas adjacent the Antarctic coastline. The minimum area of sea ice naturally occurs in February and the maximum in September.
Product: ARTIST (ASI 5) (Spreen et al. 2008)
Source: Universität Bremen
Resolution: 6.125 km nominal
Timeframe: 2012 to present
Notes: Concentrations of less than 15% have been removed.
Name: Monthly Sea Ice Concentration
Desc: Sea ice concentration is a measure of the amount of size ice over an area. It is calculated from satellite observations of sea ice for all areas adjacent the Antarctic coastline. The minimum area of sea ice naturally occurs in February and the maximum in September.
Product: Sea Ice Index (Windnagel et al. 2017)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: 25 km nominal
Timeframe: 1980 to present
Notes: Concentrations of less than 15% have been removed.
Name: Monthly Anomalies in Sea Ice Concentration
Desc: Anomalies in sea ice concentration show the monthly variation from the long term mean.
Product: Climate Data Record and Near Real-Time Sea Ice Concentration (Windnagel et al. 2021)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: 25km nominal
Timeframe: 1980 to present
Notes: Anomalies are calculated as the difference between the sea ice concentration and the 1981-2010 mean sea ice concentration for that month. Anomalies less than 7.5% are not shown.
Name: Long term monthly mean sea ice extent
Desc: Sea ice extent is calculated as contour lines at 15% and 80% sea ice concentration.
Product: Sea Ice Index (Windnagel et al. 2017)
Source: Climate Data Record and Near Real-Time Sea Ice Concentration (Windnagel et al. 2021)
Resolution: -
Timeframe: 1980 to present
Notes: Contours with less than 15 vertices are discarded.
Name: Long Term Monthly Mean Sea Ice Extent
Desc: Mean monthly sea ice extent over the 1981-2010 time interval. This is calculated as contour lines at 15% and 80% long term mean (1981-2010) sea ice concentration.
Product: Sea Ice Index (Windnagel et al. 2017)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: -
Timeframe: Long term monthly mean (1981-2010)
Notes: Contours with less than 15 vertices are discarded.
Name: Gridded Freeboard (ATL20) IceSat2
Desc: Sea ice freeboard is the distance between the waterline and the surface height of sea ice in open leads. This dataset contains monthly gridded estimates of sea ice freeboard, derived from along-track freeboard estimates in the ATLAS/ICESat-2 L3A Sea Ice Freeboard product (ATL10,V3).
Product: ATL20 (Petty et al. 2020)
Source: NSIDC
Resolution: 25 km nominal
Timeframe: Oct 2018 to July 2022
Notes: Data greater than 1 metre is shown as 1 metre height.
Name: Annual Sea Ice Duration
Desc: Sea ice duration (contour lines) is the number of days sea ice concentrations above 15% occur between consecutive sea ice minima (assumed to occur on Feb 16 each year).
Product: Climate Data Record and Near Real-Time Sea Ice Concentration (Windnagel et al. 2021)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: 25km nominal
Timeframe: 1980 to 2021
Notes:
Name: Sea Ice Duration Anomalies
Desc: Anomalies in sea ice duration show difference in duration of sea ice from the long term mean, where sea ice duration is the number of days sea ice concentrations above 15% occur between consecutive sea ice minima.
Product: Climate Data Record and Near Real-Time Sea Ice Concentration (Windnagel et al. 2021)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: 25km nominal
Timeframe: 1980 to 2021
Notes: Anomalies in sea ice duration are calculated relative to the 1981 to 2010 mean.
Name: Annual Sea Ice Advance
Desc: Sea ice advance is the date when sea ice concentrations persist above 15% after the sea ice minimum.
Product: Climate Data Record and Near Real-Time Sea Ice Concentration (Windnagel et al. 2021)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: 25km nominal
Timeframe: 1980 to 2022
Notes:
Name: Sea Ice Advance Anomalies
Desc: Anomalies in sea ice advance show number of days (early/late) from the long term mean, where sea ice advance is the date when sea ice concentrations persist above 15% after the sea ice minimum.
Product: Climate Data Record and Near Real-Time Sea Ice Concentration (Windnagel et al. 2021)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: 25km nominal
Timeframe: 1980 to 2022
Notes: Anomalies in sea ice advance are calculated relative to the 1981 to 2010 mean.
Name: Annual Sea Ice Retreat
Desc: Sea ice retreat is the date when sea ice concentrations persist below 15% occur after the sea ice maximum.
Product: Climate Data Record and Near Real-Time Sea Ice Concentration (Windnagel et al. 2021)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: 25km nominal
Timeframe: 1980 to 2021
Notes:
Name: Annual Sea Ice Retreat
Desc: Anomalies in sea ice retreat show number of days (early/late) from the long term mean, where sea ice retreat is the date when sea ice concentrations persist below 15% occur after the sea ice maximum.
Product: Climate Data Record and Near Real-Time Sea Ice Concentration (Windnagel et al. 2021)
Source: NSIDC (National Snow and Ice Data Center)
Resolution: 25km nominal
Timeframe: 1980 to 2021
Notes: Anomalies in sea ice retreat are calculated relative to the 1981 to 2010 mean.
Name: Monthly Chlorophyll Concentration
Desc: Chlorophyll-a is a proxy for phytoplankton activity in the ocean and is estimated through ocean colour remote sensing.
Product: Ocean Colour Climate Change Initiative (Sathyendranath et al. 2019)
Source: Ocean Colour
Resolution: 4km nominal, displayed at 10km
Timeframe: 1998-Jun 2022
Notes: This product relies on reflectance in the visible spectrum and does not perform well at Southern Hemisphere high latitudes during periods of low light (April to August) or where there is dense sea ice cover.
Name: Monthly Chlorophyll Concentration Anomalies
Desc: Anomalies in the monthly chlorophyll concentration are calculated relative to the 1998-2020 average for that month.
Product: Ocean Colour Climate Change Initiative (Sathyendranath et al. 2019)
Source: Ocean Colour
Resolution: 4km nominal, displayed at 10km
Timeframe: 1998-Jun 2022
Notes: This product relies on reflectance in the visible spectrum and does not perform well at Southern Hemisphere high latitudes during periods of low light (April to August) or where there is dense sea ice cover.
Name: Monthly Sea Surface Temperature
Desc: Sea Surface Temperature (SST) is an estimate of the water temperature at the ocean surface calculated from satellite and surface observations.
Product: Met Office OSTIA (Operational Sea Surface Temperature and Sea Ice Analysis) Near Real Time (Good et al. 2020)
Source: Copernicus
Resolution: 0.05° × 0.05° Nominal
Timeframe: Oct 1981 to present
Notes: There is limited validation of SST remote sensing datasets in the marginal ice zone and close to Antarctica. SST within polynyas and within areas of low concentration sea ice are included but not well validated. Where SST under high concentration sea ice cannot be calculated from observations, it defaults to -1.8°C.
Name: Monthly Sea Surface Temperature Anomalies
Desc: Anomalies in the monthly Sea Surface Temperature (SST) are calculated relative to the 1981 to 2010 average for that month.
Product: Met Office OSTIA (Operational Sea Surface Temperature and Sea Ice Analysis) Near Real Time (Good et al. 2020)
Source: Copernicus
Resolution: 0.05° × 0.05° Nominal
Timeframe: Oct 1981 to present
Notes: There is limited validation of SST remote sensing datasets in the marginal ice zone and close to Antarctica. SST within polynyas and within areas of low concentration sea ice are included but not well validated. Where SST under high concentration sea ice cannot be calculated from observations, it defaults to -1.8°C.
Name: International Bathymetric Chart of the Southern Ocean Version 2 (IBCSO v2) (Dorschel et al. 2022)
Desc: Bathymetry is a measure of the depth of the ocean, provided for the areas south of 50° S. The product chosen is a digital bathymetric model for the area south of 50° S with special emphasis on the bathymetry of the Southern Ocean. The total data coverage of the seafloor is 23.79% with a multibeam-only data coverage of 22.32%. The remaining 1.47% include singlebeam and other data.
Product: International Bathymetric Chart of the Southern Ocean Version 2 (IBCSO v2) (Dorschel et al. 2022)
Source: Pangaea
Resolution: 5km nominal
Timeframe: Released 2022
Notes: The source product is provided at 500m nominal resolution, which has been regridded to the 5km nominal resolution displayed.
See the metadata record "AAS_4506_NILAS_SOFTWARE" for information about the Nilas software package.
