Sea-ice age for Arctic from NSIDC

Ice age week 22 — Sea ice age distribution for the Arctic for week 22 of the years 1995, 2005, and 2015. Numbers 1, 2, 3, etc. denote first-year ice, i.e. sea ice of the current freezing season, second-year ice (has survived one summer melt season), third-year ice (has survived two summer melt seasons) , and so on. Copyright: UHH/CEN/AJB

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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.

View sea ice age data at LAS
Access sea ice age data via OPeNDAP
Data access via file system: /data/icdc/ice_and_snow/arctic_sea_ice_age

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Description

Sea ice concentration and sea ice drift based on satellite data are used to investigate sea ice drift trajectories. First, the sea ice extent is calculated for every week. Only grid cells with at least 15% sea ice concentration contribute to the extent. Each of these grid cells is treated as a Lagrange particle which moves according to the mean weekly sea ice drift (derived from the NSIDC ice drift data set). The position of that cell is tracked for every week and the number of weeks the particle remains inside the area given by the sea ice extent, which is calculated anew for every week, is summed up which gives the age. If the particle is located outside this area after its translation due to the sea ice drift then it is assumed that the sea ice in that grid cell has melted. Every year in September, between week 37 and 38, upon commence of freezing conditions the age of all still existing grid cells is rounded up to the successive full year, e.g. a grid cell of age 45 weeks with > 15% first-year ice (rest is open water) becomes 2nd-year ice (images at top: "1" --> "2") while a grid cell of the age 2 years and 50 weeks i.e. 3rd-year ice of > 15% (rest is open water) becomes 4th-year ice (in images at top: "3" --> "4").

Co-existence of ice of different age in one grid cells results in the survive of the older one in order to take into account that younger and hence thinner sea ice deforms and melts more easily. Also here a threshold value of 15% is used: A grid cell with 15% ice 6 years old and 85% first-year ice is assigned 6-year old ice.

See the references for more details about the method and possible applications.

This is the NSIDC Arctic Sea Ice Age data set version 4.1 (see references).

Due to visualisation reason, seasonal sea ice, i.e. the sea ice of the current winter, is assigned an age of 1 year. The reading of the sea-ice age is as follows: first-year sea ice (from the current winter, i.e. is in its first year, therefore = 1), second-year sea ice (has survived on melting season, is in its second year, therefore = 2), third-year sea ice (has survived two melting seasons), and so on.

Last update of data set at ICDC: October 24, 2024.

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Parameters

Parameters of the sea ice age data set
Name	Unit (Range)	Comment
Sea ice age	years (0 ... 16)	0 = open water 1 = first-year ice 2 = second-year ice ... and so on 16 = 16-year old ice 20 = land 21 = lakes / too close to coast

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Coverage, spatial and temporal resolution

Period and temporal resolution:

1984-01-01 until 2023-12-31
Weekly

Coverage and spatial resolution:

Northern hemisphere
Spatial resolution: 12.5 km x 12.5 km, EASE-Projection with a NSIDC Na12500-CF.gpd grid (see references)
Geographic longitude: 0°E to 360°E
Geographic latitude: 48.4°N to 90°N
Dimension: 721 columns x 721 rows
Altitude: 0.0 m

Format:

NetCDF

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Data quality

The data set does not contain uncertainty estimates. The approach uses weekly values of sea ice concentration and sea ice drift; random uncertainties in these daily products are therefore reduced.

Largest uncertainties can be expected during melt conditions and also in the marginal ice zone when and where both sea ice concentration and drift have the largest uncertainties.

It cannot be excluded that the ice age is - in general - positively biased because of the preferential assignment of the age of the oldest class to the entire grid cell - for concentrations of that oldest class down to 15% at the end of summer.

It cannot be excluded that potential inconsistencies in the sea ice drift data set used have an impact on the sea ice age derived. In this context we note, that the sea ice drift data set is based on a heterogeneous mixture of different data sources.

We note that for the first years of the data set the typical distribution of sea ice age classes is possibly not yet fully developed due to the methodology used. It lacks data of sea ice older than 7 years.

For further details and discussion of uncertainties and error sources we refer to the references.

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Contact

Technical Contact:
National Snow and Ice Data Centre (NSIDC)
email: nsidc (at) nsidc.org

Investigators
Walt Meier
NASA Goddard Space Flight Center (GSFC)
email: walt.meier (at) nasa.gov

Scott Steward
CCAR, University of Colorado, UCB 449, Boulder, CO
email: scottincolorado (at) gmail.com

Mark Tschudi
CCAR, University of Colorado, UCB 431, Boulder, CO
email: mark.tschudi (at) colorado.edu

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

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References

Literature:

Fowler, C., et al., Satellite-derived evolution of Arctic sea ice age: October 1978 to March 2003. Geosci. Rem. Sens. Lett., 1(2), 71-74, 2004, doi: 10.1109/LGRS.2004.824741
Rigor, I.G., and J.M. Wallace, Variations in the age of Arctic sea-ice and summer sea-ice extent. Geophys. Res. Lett., 31(L09401), 2004, doi: 10.1029/2004GL019492
Maslanik, J., et al., Distribution and trends in Arctic sea ice age through spring 2011. Geophys. Res. Lett., 38(L13502), 2011, doi: 10.1029/2011GL047735
Tschudi, M. A., et al., Tracking the movement and changing surface characteristics of Arctic sea ice. J. Selected Topics in Earth Obs. Rem. Sens., 3(4), 2010, doi: 10.1109/JSTARS.2010.2048305
Korosov, A. A., et al., A new tracking algorithm for sea ice age distribution estimation. The Cryosphere, 12, 2073-2085, 2018, doi: 10.5194/tc-12-2073-2018

Websites:

NSIDC Arctic Sea Ice Age data set version 4.1, http://nsidc.org/data/nsidc-0611
EASE-Projection, http://nsidc.org/data/ease/
NSIDC maps for Na12500-CF.gpd grid, ftp://sidads.colorado.edu/pub/tools/mapx/nsidc_maps/

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Data citation

Please cite the data as follows:

Tschudi, M., W. N. Meier, J. S. Stewart, C. Fowler, and J. Maslanik. 2024. EASE-Grid Sea Ice Age, Version 4.1, [indicate subset used]. Boulder, Colorado USA: NASA National Snow and Ice Data Center Distributed Active Archive Center. https://nsidc.org/data/nsidcc-0611. https://doi.org/10.5067/UTAV7490FEPB [last access date: October 21, 2024].

and with the following acknowledgments:

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

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