Polar sea-ice concentration from OSI SAF

Eumetsat OSI-SAF OSI-450a sea-ice concentration map for February 16 2012 for the Northern Hemisphere. Copyright: EUMETSAT

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Access

RESTRICTED: This link to the data set is only available for a restricted user group. The data set is only accessible in CEN/MPI net or accessible from external nets with a customer account. Please contact ICDC if you would like to access this data from outside the network or navigate to https://osi-saf.eumetsat.int/products/sea-ice-products.

View OSI-SAF sea ice data at LAS
Access OSI-SAF sea ice data via OPeNDAP
Data access via file system: /data/icdc/ice_and_snow/osisaf_iceconc/ [v3.0 in DATA/, v2.0 in DATA_OLD]

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Description

This is the fully reprocessed v3.0 EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF) team Sea-Ice Concentration (SIC) Climate Data Record (CDR) OSI-450a and its extension, the interim CDR (ICDR) OSI-430a. These product supersede the v2.0 products OSI-450 and OSI-430b. Processing chains are identical for OSI-450a and OSI-430a. Sea-ice concentrations over the polar regions are derived from passive microwave satellite data of SMMR, SSM/I and SSMIS, covering years 1978 to 2024. More recent ICDR data extending this data set to toady minus 16 days is available at the OSI-SAF Website (see references).

The basic principles and methodologies that were the backbone of the previous CDR (OSI-450) are still featured in OSI-450a (e.g. atmospheric correction of brightness temperature with NWP re-analysis data, state of the art algorithms, dynamic tie-points, uncertainties, etc...). They were nevertheless all revisited for this new release, through dedicated R&D in the OSI SAF project and in the ESA Climate Change Initiative Sea Ice projects, whose contribution is acknowledged. Key improvements embedded in OSI-450a are more accurate and stable algorithms, a correction of the weather influence on the level 2 data based on ERA5 data - now including cloud liquid water, and an improved land-water mask. There is more information in the references. The Algorithm Theoretical Basis Document (ATBD), the Product User Manual and the Validation Report give details about the sea-ice concentration retrieval, additional filters, optimization procedures, and the error estimation as well as some aspects about the validation.

Spatial error correlation length scales derived from v2.0 of the product, i.e. OSI-450, of the years 2002-2011 can be accessed here: https://doi.org/10.25592/uhhfdm.10415 here.

Last update of data set at ICDC: August 8, 2024

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Parameters

Parameters of the OSI-SAF sea ice data set. For information about the status flag see Product User Manual page 21/22.
Name	Range
Main (filtered) sea-ice concentration	0% ... 100%
Raw sea-ice concentration	< 0% ... > 100%
Total standard uncertainty	0% ... 100%
Smearing standard uncertainty	0% ... 100%
Algorithm standard uncertainty	0% ... 100%
Status flag (bit coded)	0 ... 255

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Coverage, spatial and temporal resolution

Period and temporal resolution:

1978-10-25 to 1987-08-20
Every other day
1987-08-21 to 2024-06-30 (CDR until 2020-12-31, ICDR afterwards)
Daily (Monthly data are available on request)

Coverage and spatial resolution:

Northern and Southern Hemisphere
Spatial resolution: 25 km x 25 km, EASE2 grid (see http://nsidc.org/data/ease/ )
Geographic longitude: 0°E to 360°E
Geographic latitude: about 41°N and 41°S to 90°N and 90°S, respectively, coverage is larger in the grid corners
Dimensions: 432 columns x 432 rows
Altitude: 0.0 m

Format:

NetCDF

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Data quality

For each grid cell and each available day an error estimate and a status flag is given.

The error estimates describe the uncertainty inherent in the retrieval, i.e. due to the input data used, and from the tie points and the uncertainties caused by gridding sea-ice concentrations which are computed at footprint level into the used EASE2 grid.

The status flag provides information about the surface type and whether values are the originally retrieved ones or whether they are the result of flagging and/or interpolation.

The unfiltered sea-ice concentration data set is for the more advanced users and is described in the Product User Manual. Missing days are given in the Product User Manual as well, see references.

A visual quality check of the product revealed dates when the sea-ice concentration distribution maps contain artefacts - due to spatio-temporal interpolation, corrupt input satellite data, or other yet unknown impact factors, and when the maps show patches of spurious sea-ice concentration over open water of size > 4-5 grid cells; the dates are listed in this document.

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Contact

Thomas Lavergne
Norwegian Meteorological Institute (met.no)
email: thomas.lavergne (at) met.no

Steinar Eastwood
Norwegian Meteorological Institute
email: osisaf-manager (at) met.no

Stefan Kern
University of Hamburg
email: stefan.kern (at) uni-hamburg.de

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References

Websites:

ESA Climate Change Initiative (ESA-CCI), https://climate.esa.int/en/
ESA CCI Sea Ice Website: https://climate.esa.int/en/projects/sea-ice/
OSI SAF High Latitude Processing Center, https://osisaf-hl.met.no/

Literature:

Lavergne, T., et al., 2019, Version 2 of the EUMETSAT OSI SAF and ESA CCI Sea Ice Concentration Climate Data Records, The Cryosphere, 13(1), 49-78, https://doi.org/10.5194/tc-2018-127
Kern, S., et al., 2019, Satellite Passive Microwave Sea-Ice concentration data set inter-comparison: Closed ice and ship-based observations, The Cryosphere, 13(12), 3261-3307, https://doi.org/10.5194/tc-13-3261-2019 .
Kern, S., et al., 2020, Satellite passive microwave sea-ice concentation data set intercomparison for Arctic summer conditions, The Cryosphere, 14(7), 2469-2493, https://doi.org/10.5194/tc-14-2469-2020 .
Kern, S., et al., 2022, Satellite passive microwave sea-ice concentration data set intercomparison using Landsat data, The Cryosphere, 16(1), 349-378, https://doi.org/10.5194/tc-16-349-2022 .
ATBD for the OSI SAF Global Sea Ice Concentration Climate Data Record (pdf, not barrier free)
Global Sea Ice Concentration Climate Data Record Product User Manual for Product OSI-450a/OSI-430a/OSI-458 (pdf, not barrier free)
Sea Ice Concentration Climate Data Record Scientific Validation Report OSI-450a/OSI-430a/OSI-458 (pdf, not barrier free)

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Data citation

Please cite the data as follows:

EUMETSAT Ocean and Sea Ice Satellite Application Facility. Global sea ice concentration [interim] climate data record 1978-2020 [2021-2024]. Norwegian and Danish Meteorological Institutes. Available from osisaf.met.no., doi.org/10.15770/EUM_SAF_OSI_0013 [EUM_SAF_OSI_0014] [last accessed August 02 2024].

All intellectual property rights of the OSI SAF products belong to EUMETSAT. The use of these products is granted to every interested user, free of charge. If you wish to use these products, EUMETSAT copyright credit must be shown by displaying the words "copyright (year) EUMETSAT" on each of the products used.

and with the following acknowledgments:

Thanks to ICDC, CEN, University of Hamburg for data support.

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