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CENIntegrated Climate Data Center ICDC

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Sea-Ice Area Product from UHH

Arctic sea-ice area for month September 1950-2020 from UHH-SIA product.
UHH-SIA product example: Arctic sea-ice area for month September 1950-2023 derived from different satellite data. Copyright: UHH/QuentinRauschenbach

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Access

UNRESTRICTED:

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.

  • Data access via file system: /data/icdc/ice_and_snow/uhh_seaiceareatimeseries/

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Description

The UHH sea-ice area product offered here contains time series of the monthly mean sea-ice area for both Polar regions. These time series are computed from the following publicly available gridded sea-ice concentration products: OSI-450a / OSI-430a at ICDC, ESA-CCI+ Higher resolution SIC product, as well as  Walsh (v2), NASA-Team, Comiso-Bootstrap, and HadISST (v2) (see references).

The sea-ice area in one hemisphere is the sum of the sea-ice areas of all grid cells of the respective hemisphere. The sea-ice area of each grid cell is the product of the grid cell area and the sea-ice concentration in that grid cell. The steps to compute the sea-ice area for the different products are specifically tailored to their content. These are based on Climate Data Operators (CDOs) and python/numpy and are described in the following.

Walsh: This data set contains monthly mean sea-ice concentration data used directly to compute the sea-ice area (SIA). We do not need to fill temporal or spatial data gaps. However, for the time period prior to the era of routine satellite observations of the polar regions (winter 1978/79) the sources (ship-, ground- and air-borne observations and reports) used to generate this data set contain many temporal and spatial gaps which were filled (see Walsh et al 2019 in references).

OSI-450a/OSI-430a/ESA-CCI+: First we compute the daily SIA from the daily sea-ice concentration data. We do not need to fill spatial data gaps. We fill temporal data gaps in the daily SIA time series of up to seven days duration by linear interpolation prior to the computation of the monthly mean SIA. For months containing temporal data gaps longer than seven days we do not compute the monthly mean SIA.

NASA-Team / Comiso-Bootstrap: Before computing the daily SIA from the daily sea-ice concentration data, we need to fill two types of spatial data gaps. One is the observation gap centered at the North Pole. This gap is filled with the mean daily sea-ice concentration computed from a ring around this gap. Other spatial gaps in the daily sea-ice concentration are filled by linear interpolation over time using values of the previous and the next day - provided that these data gaps cover less than 1000 non-contiguous grid cells. In case more grid cells are affected no daily SIA value is computed for the respective day. Subsquently, we compute the daily SIA from the gap-filled daily sea-ice concentration data. Gaps in the resulting daily SIA time series are treated similar to OSI-450/OSI-430-b before we compute the monthly SIA values. For months containing temporal data gaps longer than seven days we do not compute the monthly mean SIA.

HadISST: This data set contains monthly mean sea-ice concentration data used directly to compute the SIA. We do not need to fill temporal or spatial data gaps. Like the Walsh data set, the HadISST data set includes a substantial amount of data based on gap-filling methods and climatologies for the time period prior to the era of routine satellite observations. The HadISST data set utilizes a very conservative land-sea mask. In order to make HadISST SIA values more comparable to the other products, we interpolate the monthly HadISST sea-ice concentration data onto the NSIDC grid (used e.g. by NASA-Team / Comiso-Bootstrap) and provide an additional HadISST SIA time series for which we employ the NSIDC land-sea mask.

Last update of data set at ICDC:  March 5, 2024.

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Parameters

Parameters of the UHH-SIA data set
NameUnitNHSH
Sea-ice area Walsh 10e6 km² x  
Sea-ice area HadISST original 10e6 km² x x
Sea-ice area HadISST NSIDC 10e6 km² x x
Sea-ice area NASA-Team 10e6 km² x x
Sea-ice area Comiso-Bootstrap 10e6 km² x x
Sea-ice area OSI-450a/OSI-430a 10e6 km² x x
Sea-ice area ESA-CCI+ 10e6 km² x x


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Coverage, spatial and temporal resolution

Period and temporal resolution:

  • 1850-01 to 2023-12
  • monthly

Coverage and spatial resolution:

  • Northern and Southern Hemisphere
  • Spatial resolution: Northern and Southern Hemisphere
  • Geographic longitude: 0°E to 360°E
  • Geographic latitude: about 30°N and 30°S to 90°N and 90°S, respectively
  • Dimensions: 2088 rows
  • Altitude: 0.0 m

Format:

  • NetCDF

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Data quality

The data set does not contain an estimate of the uncertainty.

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Contact

Jakob Doerr
Geophysical Institute / University of Bergen
E-Mail: uhhsia.ifm (at) uni-hamburg.de

Quentin Rauschenbach
Institute of Oceanography / University of Hamburg
E-Mail: quentin.rauschenbach (at) studium.uni-hamburg.de

Dirk Notz
Institute of Oceanography / University of Hamburg
E-Mail: uhhsia.ifm (at) uni-hamburg.de

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

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References

Literature:

  • Walsh, J. E., W. L. Chapman, F. Fetterer, and S. Stewart. 2019. Gridded Monthly Sea Ice Extent and Concentration, 1850 Onward, Version 2. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: https://doi.org/10.7265/jj4s-tq79 .
  • Walsh, J. E., et al., 2017, A database for depicting Arctic sea ice variations back to 1850. Geographical Review, 107(1), 89-107.
  • Titchner, H. A., and N. A. Rayner, 2014, The Met Office Hadley Centre sea ice and sea surface temperature data set, version 2: 1. Sea ice concentrations, J. Geophys. Res.-Atmospheres, 119, 2864-2889, https://doi.org/10.1002/2013JD020316 .
  • 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 .
  • Lavergne, T., et al., 2023, Monitoring of Sea Ice Concentration, Area, and Extent in the polar regions : 40+ years of data from
    EUMETSAT OSI SAF and ESA CCI, IAF Global Space Conference on Climate Change (GLOC 2023), 23-25 May 2023,
    Oslo, Norway. https://www.iafastro.org/ , https://zenodo.org/records/10014535
  • 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 concentration data set intercomparison for Arctic summer conditions, The Cryosphere, 14(7), 2469-2493, https://doi.org/10.5194/tc-14-2469-2020 .

Websites:

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Data citation, License, and Acknowledgments

Please cite the data as follows:

Rauschenbach, Q., Dörr, J., Notz, D., and Kern, S., 2024, UHH sea-ice area product, 1850-2023, University of Hamburg, v2024_fv0.01, https://doi.org/10.25592/uhhfdm.11346, last access date YYYY-MM-DD [fill in date that applies]

Licence: The data was published under the Creative Commons Attribution 4.0 International License (CC-BY-4.0).

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