For a list of known issues with this product, see the Known Issues document under the Technical References tab.
Selected granules for ATL03 and associated products (ATL04, ATL06, ATL07, ATL08, ATL09, ATL10, ATL12, ATL13) have been recalled and will be released at a later time. For a list of recalled data, see the 'Retracted Data File List' document under Technical References.
Data Set ID: 

ATLAS/ICESat-2 L3A Ocean Surface Height, Version 3

This data set (ATL12) contains along-track sea surface heights at variable length scales over cloud-free regions. Estimates of height distributions, surface roughness, surface slope, and apparent reflectance are also provided. The data were acquired by the Advanced Topographic Laser Altimeter System (ATLAS) instrument on board the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) observatory.

This is the most recent version of these data.

Version Summary: 

Changes for this version include:

  • The parameters gt[x]/ssh_segments/heights/xbind, gt[x]/ssh_segments/heights/htybin, gt[x]/ssh_segments/heights/xrbin, and ds_xbin were added to the product to report 10 m bin average heights and averaged photon rate information output by the sea state bias calculation.
  • The ocean histograms were updated to have a center bin with a zero height, consistent with the ATBD.
  • New scatter plots were added to the browse images to better visualize the data. Previous browse images for heights and ground tracks (as well as new plots) are now separated by orbit.
  • The width of the received histogram as determined in fine_sel is now used to create the y histogram in rm_uncertainty, which is then used in char_rss to create simulated photons that are used in fit2g to determine a two Gaussian fit.
  • The moments of Y are now calculated as described in the ATBD for ATL12.
  • The h_kurtosis calculation has been corrected to match the description in the ATBD for ATL12.
  • The length_seg parameter is now calculated as the difference of the along-track x of the first and last signal photons in the ocean segment. This calculation is now consistent with the ATBD for ATL12.
  • A new formula for calculating the 10-m bin average photon rate was implemented.

COMPREHENSIVE Level of Service

Data: Data integrity and usability verified; data customization services available for select data

Documentation: Key metadata and comprehensive user guide available

User Support: Assistance with data access and usage; guidance on use of data in tools and data customization services

See All Level of Service Details

Data Format(s):
  • HDF5
Spatial Coverage:
N: 90, 
S: -90, 
E: 180, 
W: -180
Spatial Resolution:
  • Varies
Temporal Coverage:
  • 13 October 2018
Temporal Resolution91 dayMetadata XML:View Metadata Record
Data Contributor(s):James Morison, David Hancock, Suzanne Dickinson, John Robbins, Leeann Roberts, et al

Geographic Coverage

Other Access Options

Other Access Options


As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Morison, J. H., D. Hancock, S. Dickinson, J. Robbins, L. Roberts, R. Kwok, S. P. Palm, B. Smith, M. F. Jasinski, and the ICESat-2 Science Team. 2020. ATLAS/ICESat-2 L3A Ocean Surface Height, Version 3. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: [Date Accessed].

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How To

Programmatic Data Access Guide
Data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) can be accessed directly from our HTTPS file system or through our Application Programming Interface (API). Our API offers you the ability to order data using specific temporal and spatial filters... read more
ICESat, IceBridge, and ICESat-2: A primer on data access across the three missions
This guide will provide an overview of the altimetry measurements and data sets across the missions, as well as a guide for accessing the data through NASA Earthdata Search and programmatically using an Application Programming Interface (API). Overview  The NASA ICESat, Operation IceBridge, and... read more
Explore, Access, and Customize ICESat-2 data at the NASA NSIDC DAAC
This webinar introduces the ICESat-2 mission and shows you how to explore, access and customize ICESat-2 data with the OpenAltimetry application, using NSIDC DAAC tools, and shows you how to subset, reformat and analyze the data using Python. This webinar was originally presented on July 23, 2019... read more
Search, order, and customize NSIDC DAAC data with NASA Earthdata Search
NASA Earthdata Search is a map-based interface where a user can search for Earth science data, filter results based on spatial and temporal constraints, and order data with customizations including re-formatting, re-projecting, and spatial and parameter subsetting. Thousands of Earth science data... read more
Filter and order from a data set web page
Many NSIDC data set web pages provide the ability to search and filter data with spatial and temporal contstraints using a map-based interface. This article outlines how to order NSIDC DAAC data using advanced searching and filtering.  Step 1: Go to a data set web page This article will use the... read more


What subsetting and reformatting services are available for ICESat-2 data?
The following table describes the subsetting and reformatting services that are currently available for ICESat-2 data via the NASA Earthdata Search tool, along with ... read more
How do I convert an HDF5/HDF-EOS5 file into binary format?
To convert HDF5 files into binary format you will need to use the h5dump utility, which is part of the HDF5 distribution available from the HDF Group. How you install HDF5 depends on your operating system. Full instructions for installing and using h5dump on Mac/Unix and... read more