edu.ucar.opensky::articles:17563 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T04:03:18.676091 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d73f4r05 Late-twentieth-century simulation of Arctic sea ice and ocean properties in the CCSM4 2012-03-01T00:00:00Z publication https://n2t.org/ark:/85065/d73f4r05 https://doi.org/10.1175/JCLI-D-11-00201.1 Jahn, Alexandra author Sterling, K. author Holland, Marika M. author Kay, Jennifer author Maslanik, J. author Bitz, C. author Bailey, David A. author Stroeve, J. author Hunke, E. author Lipscomb, W. author Pollak, D. author UCAR/NCAR - Library publisher To establish how well the new Community Climate System model version 4 (CCSM4) simulates the properties of the Arctic sea ice and ocean, we here compare results from six CCSM4 20th century ensemble simulations with available data. We find that the CCSM4 simulations capture most of the important climatological features of the Arctic sea ice and ocean state well, among them the sea-ice thickness distribution, the fraction of multiyear sea ice, and the sea-ice edge. The strongest bias exists in the simulated spring to fall sea-ice motion field, the location of the Beaufort Gyre, and the temperature of the deep Arctic Ocean (below 250 m), which are caused by deficiencies in the simulation of the Arctic sea-level pressure field and the lack of deep-water formation on the Arctic shelves. The observed decrease in the sea-ice extent and of the multiyear ice cover is also well captured by the CCSM4. It is important to note, however, that the temporal evolution of the simulated Arctic sea-ice cover over the satellite era is strongly influenced by internal variability. For example, while one ensemble member shows an even larger decrease in the sea-ice extent over 1981 - 2005 than observed, two ensemble members show no statistically significant trend over he same period. It is therefore important to compare the observed sea-ice extent trend not just with the ensemble mean or a multi-model ensemble mean, but also with individual ensemble members, due to the strong imprint of internal variability on these relatively short trends. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2012 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work. None eng geoscientificInformation