Signy Island camera image files of sea-ice coverage for 2004; played as a movie.

The South Orkney Fast-Ice series (SOFI) is an annual record of the timing of formation and breakout of fast-ice in a bay in the South Orkney Islands on the Scotia Arc in the northern Weddell Sea, Antarctica.

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.

The HadGEM3 (HadGEM3-GC3.1 or HadGEM3-GC3.1-N96ORCA1) PI simulation was initialized using the standard CMIP6 protocol using constant 1850 GHGs, ozone, solar, tropospheric aerosol, stratospheric volcanic aerosol and land-use forcing. The PI spin-up was 700 model-years, which allowed the land and oceanic masses to attain approximate steady state. The HadGEM3 LIG (Last Interglacial) simulation was initialized from the end of the spin-up phase of the equivalent pre-industrial (PI) simulation. After initialization, the LIG was run for 350 model-years. This 350 LIG spin-up permits the model to reach atmospheric equilibrium and to achieve an upper-ocean equilibrium. The model was then run for a further 200 model-years of LIG production run. This has been demonstrated to be an adequate run length to appropriately capture the model internal variability. This dataset contains outputs from the 200 years of production run of the period. The HadCM3 PI simulation was run for a period of over 600 years. The HadCM3 LIG simulation was initialized from the end of a previous CMIP5 LIG simulation, which was of length 400 years and initiated from the end of the corresponding PI, and run for further 250 years. The total spin-up phase for the HadCM3 LIG simulation used in this study was thus 600 model-years, and the length of the production (at atmospheric and upper-oceanic equilibrium) LIG HadCM3 simulation is 50 model-years. This work was funded by NERC standard research grant nos. NE/P013279/1 and NE/P009271/1.

This data set comprises sea ice-related biomarkers for three time intervals, corresponding to the pre-MPT (1.53-1.36 Ma), the MPT (1.22-0.8 Ma), and the post-MPT (0.5-0.34 Ma) climate cycles from International Ocean Discovery Program (IODP) Site U1343 in the eastern Bering Sea (57deg33.4''N, 176deg49.0''W, 1950 m water depth). The biomarkers are the Arctic sea ice biomarker IP25, together with HBI III and brassicasterol, indicative of open water in the ice marginal zone and general phytoplankton production, respectively. Funding was provided by the NERC grant NE/L002434/1.

This dataset contains the floe size distribution (FSD) data derived from multi-satellite imagery data acquired across the Arctic Ocean. Satellite imagery data includes high-resolution visible images from the USGS Global Fiducials Library (MEDEA), TerraSAR-X/TanDEM-X and Worldview-3 (WV3). The derived data contain floe size (calliper diameter), shape factor, minor/major axis, perimeter and area of the floes. This data set has been used to investigate the characteristics of the FSD during major seasonal evaluation stages of Arctic sea ice floes. The retrieval of the FSD data was done by the University of Huddersfield team. This work was funded by NERC MOSAiC program NE/S002545/1.

This dataset contains the floe size distribution (FSD) data derived from high-resolution satellite imagery data acquired at two fixed locations in the Arctic Ocean. Satellite imagery data include MEDEA images and WorldView images. These satellite images have a spatial resolution of 1 m or higher, thus providing the FSD information, especially for small floes. The derived data contain floe size (calliper diameter), shape factor, minor/major axis, perimeter and area of the floes. This dataset has been used to evaluate the sea ice models with the FSD parameterisations. The retrieval of the FSD data was done by the University of Huddersfield team. This work was funded by NERC standard grant NE/R000654/1 and NERC MOSAiC program NE/S002545/1.

This dataset provides a 308 year record of methansulphonic acid (MSA) from coastal West Antarctica, representing sea ice conditions in the Amundsen-Ross Sea. Annual average MSA has been calculated from the 136 m Ferrigno ice core (F10), drilled on the Bryan Coast in Ellsworth Land, West Antarctica during the austral summer 2010/11. The sea ice extent is based on geometric mean regression of MSA flux with satellite sea ice extent from 146 degrees west. The record was measured using a Dionex ICS2500 anion system at 5 cm resolution, corresponding to approximately 14 samples a year. Funding was provided by the NERC grant NE/J020710/1.

The dataset (FSD-GFL-res2m-Preponding) contains sea-ice floe ice distribution (FSD) data derived from the Global Fiducials Library (GFL) imagery during the pre-ponding period at the three fiducial sites, using the algorithms described in Hwang et al. (2017). The GFL imagery is 1-m resolution declassified National Technical Means satellite imagery, also known as the Literal Image Derived Products (LIDPs) (Kwok, 2014). The FSD data derived from the GFL imagery cover the period of 2000 to 2014 at the three fiducial sites at Chukchi Sea (70 deg N and 170 deg W), East Siberian Sea (82 deg N and 150 deg E), and Fram Strait (84.9 deg N and 0.5 deg E). For the production of this dataset, the spatial resolution of the GFL imagery degraded to 2 meters ("res2m") for fast processing. The FSD data are produced for robust model calibration and validation for FSD parameterisations within sea-ice models, and also to improve our understanding of spatial and temporal variations of FSD across the Arctic Ocean. The FSD data have been generated by B. Hwang. This FSD dataset is produced as part of NERC MIZ NE/R000654/1 (Towards a marginal Arctic sea ice cover).

The South Orkney Fast-Ice series (SOFI) is an annual record of the timing of formation and breakout of fast-ice in Factory Cove, Signy Island, in the South Orkney Islands on the Scotia Arc in the northern Weddell Sea, Antarctica. Fast-ice formation and break-up has been studied at the South Orkeny Islands since the early 1900s, with this dataset covering the period of 1903 to 2019. This dataset is produced by personnel from the British Antarctic Survey, in efforts to study sea-ice variability in the Southern Hemisphere. Data was collected using various methods over the reporting period, namely an offset date from Laurie Island''s fast-ice, direct observation, and with camera equipment. This is an updated version (2.0) of the dataset, that includes data from 2008 to 2019.