Licensed under CC BY 4.0 by EUMETSAT
Sea-Ice Index, version 3.0
Operational Climate productThe Sea Ice Index is a climate indicator of sea-ice coverage. The index covers time series of sea-ice extent and area, complemented by standard statistics, climate normals, anomalies and long-term trends. The product consists of regularly updated data files (in netCDF and text formats) for users wish to analyse and visualise the data themselves. In addition, graphical products (in PNG format) illustrate the evolution and long-term trends of sea ice at global, hemispheric and regional scales. The Sea Ice Index is derived from the EUMETSAT OSI SAF Global Sea Ice Concentration data sets, developed with R&D contributions from ESA CCI.
Identification
Acronym : SII
OSI SAF producer : Norwegian Meteorological Institute
Identifier : OSI-420-a
Digital object identifier (DOI) 10.15770/EUM_SAF_OSI_0026
Id for archive (APNM) : SIIN
Characteristics
Processing level : Indicator
Satellite input : SMMR, DMSP/SSM/I, DMSP/SSMIS, GCOM-W/AMSR2
Temporal sampling : Updated daily
Spatial coverage : Hemispherical and regional
File Format(s) : NetCDF4, PNG, TEXT
Data Access
OSI SAF FTP server
ftp://osisaf.met.no/prod/
Directory: ice/index/v3p0
OSI SAF Thredds
Accuracy Requirements
Target accuracy : Number of days in a month where the day-to-day difference of SIE and SIA <= 6
Verification/validation method : Primary validation (daily): Monitor the number of times in a month where the dayto- day difference (d2d)of the SIE and of the SIA time series (NH and SH) are over a threshold (mean(d2d) + 3×STD(d2d)).
Applications and users
Usage : Climate
History
Authorised to be operational / released :
Declared operational / released since :
On FTP server since :
First date :
Full series temporal coverage : 1978-onwards
Detailed history :
- v2.1 on the FTP server since 19/11/2020
- v2.2 on the FTP server since 06/2023
- v2.3 on the FTP server since 01/09/2025
- v3.0 on the FTP server since on 04/05/2026
Licence/Attribution/Citation
Licence : CC BY 4.0
Attribution : You must include attribution to EUMETSAT OSI SAF
Recommended citation : EUMETSAT OSI SAF, Sea-Ice Index (2026), OSI-420-a, doi:10.15770/EUM_SAF_OSI_0026
References : BibteX entry
Comments
New ticket helpdesk
The index provides time series of sea ice extent and sea ice area, which represent the total ocean area where the sea ice concentration exceeds a defined threshold versus the actual surface area covered by ice weighted by the local ice concentration.