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Sea ice

Sea-ice concentration, thickness, volume and drift: model-based reanalyses, observation-based analyses, satellite products, drift vectors and extent/area indices.

Tick two or more boxes on the left to compare them; click a column header to sort.

About resolution values — please read
  • Provided resolution is the grid spacing you download from the main provider, not the model's native resolution. The same dataset can come on different grids from different providers or products, so always check the grid of the file you actually downloaded.
  • km values are approximations at the equator (1° ≈ 111 km). Longitude spacing shrinks with cos(latitude): at 60° it is half (0.25° ≈ 14 km), so "28 km" is not 28 km everywhere.
  • Gaussian grids have uneven latitude spacing, and ocean model grids (tripolar, curvilinear) vary from place to place. Grids with different latitude and longitude spacing are written as 0.5°×0.625° (lat × lon).
  • Polar-stereographic and EASE2 grids of sea-ice satellite products are defined in km; the degree value in brackets is a simple conversion. The NSIDC polar stereographic grid matches its nominal spacing only at 70° latitude.
  • Grid spacing is not the size of the smallest feature actually resolved (effective resolution). Features are typically resolved only at several times the grid spacing, and interpolating to a finer grid adds no information.
  • Temporal resolution is the shortest interval provided. Intervals and whether a value is instantaneous, mean or accumulated differ between variables — see 'Available variables' on each dataset page.

Reanalyses

DatasetTypePeriodCoverageProvided resolutionIntervalStatus
PIOMASReanalysis1979-01 ~ 2026-02Arctic22 km (0.2°)1 dayUpdate delayed
GIOMASReanalysis1979-01 ~ 2026-01Global60 km (0.8°)1 dayUpdate delayed
neXtSIMReanalysis1993-01 ~ presentArctic3 km (0.03°)1 dayAvailable
TOPAZ4b ↔Reanalysis1991-01 ~ presentArctic & N. Atlantic12.5 km (0.11°)1 dayAvailable

Observation-based analyses

DatasetTypePeriodCoverageProvided resolutionIntervalStatus
OISST (sea ice concentration) ↔Observation-based analysis1981-09 ~ presentGlobal28 km (0.25°)1 dayAvailable
HadISST (sea ice concentration) ↔Observation-based analysis1870-01 ~ presentGlobal111 km (1°)1 monthBeing replaced

Satellite products

DatasetTypePeriodCoverageProvided resolutionIntervalStatus
OSI SAF (sea ice concentration)Satellite product1978-10 ~ presentBoth poles25 km (0.23°)1 dayAvailable
NOAA/NSIDC CDRSatellite product1978-10 ~ presentBoth poles25 km (0.23°)1 dayAvailable
ASI AMSR2 (Univ. Bremen) ↔Satellite product2002-06 ~ presentBoth poles6.25 km (0.06°)1 dayAvailable
CryoSat-2Satellite product2010-10 ~ presentArctic25 km (0.23°)7 daysAvailable
CS3SMOSSatellite product2023-10 ~ presentBoth poles12.5 km (0.11°)7 daysAvailable
SMOS thin sea ice thickness ↔Satellite product2010-10 ~ presentBoth poles12.5 km (0.11°)1 dayAvailable
ESA CCISatellite product1972-12 ~ 2024-04Both poles25 km (0.23°)1 dayAvailable
ICESat-2Satellite product2018-10 ~ presentBoth poles25 km (0.23°)1 dayAvailable
CS2SMOSSatellite product2010-11 ~ 2025-04Arctic25 km (0.23°)7 daysDiscontinued

Sea-ice drift

Sea-ice motion (drift) vectors tracked from satellite imagery.

DatasetTypePeriodCoverageProvided resolutionIntervalStatus
Polar PathfinderSatellite product1978-11 ~ presentBoth poles25 km (0.23°)1 dayAvailable
OSI SAF (sea ice drift)Satellite product1991-01 ~ presentBoth poles62.5 km (0.56°)1 dayAvailable

Sea-ice indices

Summary indices such as sea-ice extent and area computed from satellite sea-ice concentration.

DatasetTypePeriodCoverageProvided resolutionIntervalStatus
Sea Ice IndexSatellite product1978-10 ~ presentBoth poles25 km (0.23°)1 dayAvailable

↔ Also listed in another section.