2026-08-19T22:13:04Zhttp://nsidc.org/api/dataset/metadata/oai

oai:nsidc.org/ATL21.0032026-05-13T14:15:49Zcumulusretirednasa_nsidc_daac

ATL21.003ATLAS/ICESat-2 L3B Daily and Monthly Gridded Polar Sea Surface Height AnomalyPetty, A. A., Kwok, R., Bagnardi, M., Kurtz, N., Wimert, J., Lee, J. & Hancock, D.ATLAS/ICESat-2 L3B Daily and Monthly Gridded Polar Sea Surface Height Anomaly2023-08-24Boulder, Colorado USANASA NSIDC DAAC: NASA National Snow and Ice Data Center Distributed Active Archive Center3false10.5067/ATLAS/ATL21.003https://nsidc.org/sites/default/files/documents/user-guide/atl21-v003-userguide.pdfATL21Technical ContactNSIDCUser Servicesnsidc@nsidc.org1-303-492-61991-303-492-2468

CIRES, 449 UCB

University of Colorado

BoulderCO80309-0449USAEARTH SCIENCEOCEANSSEA SURFACE TOPOGRAPHYSEA SURFACE HEIGHTSEA SURFACE HEIGHT ANOMALY (SSHA) Climatology/Meteorology/AtmosphereElevationOceansicesat2-projectATLASAdvanced Topographic Laser Altimeter SystemICESat-2Ice, Cloud, and land Elevation Satellite-22018-10-142025-02-28deprecated-9090-180180GEOGRAPHIC REGIONGLOBAL OCEAN25 km25 km1 dayThese data have been retired and are no longer accessible, though a more recent version of these data may be available.These data have been retired and are no longer available for use, though a more recent version of these data may be available. Cite any prior or planned use of these data according to the recommended citation at https://nsidc.org/about/data-use-and-copyright. For more information on the NASA ESDIS Data Use Guidance, see https://www.earthdata.nasa.gov/engage/open-data-services-software-policies/data-use-guidance.EnglishNASA/GSFC/SED/ESD/I2-SIPSNASA NSIDC DAACNASA National Snow and Ice Data Center Distributed Active Archive Centerhttps://nsidc.org/daacData Center ContactNSIDCUser Servicesnsidc@nsidc.org1-303-492-6199

National Snow and Ice Data Center

CIRES, 449 UCB

University of Colorado

BoulderCO80309-0449USAHTTPSHDF5

ATL21 contains daily and monthly gridded polar sea surface height (SSH) anomalies, derived from the along-track ATLAS/ICESat-2 L3A Sea Ice Height product (ATL10, V6). The ATL10 product identifies leads in sea ice and establishes a reference sea surface used to estimate SSH in 10 km along-track segments. ATL21 aggregates the ATL10 along-track SSH estimates and computes daily and monthly gridded SSH anomaly in NSIDC Polar Stereographic Northern and Southern Hemisphere 25 km grids.

VIEW RELATED INFORMATIONhttps://nsidc.org/sites/default/files/documents/user-guide/atl21-v003-userguide.pdfATLAS/ICESat-2 L3B Daily and Monthly Gridded Polar Sea Surface Height Anomaly, Version 3 User GuideCEOS IDN DIFVERSION 9.92023-08-242026-05-13NSIDCVersion SummaryCorrect reported longitude values to agree with NSIDC Polar Stereographic projections; Added grid_mapping attribute to land_mask_map array; Updated the MSS variable description; Added mentions of the source of the MSS (which uses CryoSat-2 data) and clarified the use of the tide-free systemNSIDCMinor Version1

Data were reprocessed using ITRF2014 (replacing ITRF2020) for consistency across the entire data set.

2022-11-132023-10-260NSIDCSpatial Reference SystemsEPSG:3411NSIDC Sea Ice Polar Stereographic NorthEPSG:3412NSIDC Sea Ice Polar Stereographic SouthNSIDCLevel of ServiceNo Data AccessNSIDCFull Dataset CitationPetty, A. A., Kwok, R., Bagnardi, M., Kurtz, N., Wimert, J., Lee, J. & Hancock, D. (2023). <i>ATLAS/ICESat-2 L3B Daily and Monthly Gridded Polar Sea Surface Height Anomaly</i>. (ATL21, Version 3). [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. <a href="https://doi.org/10.5067/ATLAS/ATL21.003">https://doi.org/10.5067/ATLAS/ATL21.003</a>. [<i><describe subset used if applicable></i>].NSIDCRetiredtrue