•  On Wednesday, June 7, from 6:00 a.m. to 1:00 p.m. (US Mountain Time), the following data collections may not be available due to planned system maintenance: ASO, AMSR Unified, AMSR-E, Aquarius, High Mountain Asia, IceBridge, ICESat/GLAS, ICESat-2, LVIS, MEaSUREs, MODIS, Nimbus, SMAP, SnowEx, SSM/I-SSMIS and VIIRS.

  • For a list of known issues with this product, see the Known Issues document under the Documentation section of the page.

ATLAS/ICESat-2 L3A Ocean Surface Height, Version 3 (ATL12)
Data set:
There is a more 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.


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.
Data Format(s):
Temporal Coverage:
13 October 2018 to 11 November 2020
Temporal Resolution:
91 day
Spatial Resolution:
Spatial Reference System(s):
WGS 84
Spatial Coverage:
Yellow areas on the map below indicate the spatial coverage for this data set.

Data Access & Tools

This data set has been retired. There is a more recent version of these data.

Help Articles

How To

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.
Many NSIDC DAAC data sets can be accessed using the NSIDC DAAC's Data Access Tool. This tool provides the ability to search and filter data with spatial and temporal constraints using a map-based interface. Users have the option to
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.
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).
All 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, using wget or curl. Basic command line instructions are provided in the article below. 
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.

Getting started

This article covers frequently asked questions about the NASA NSIDC DAAC's Earthdata cloud migration project and what it means to data users.
The NASA Earthdata Cloud is the NASA cloud-based archive of Earth observations. It is hosted by Amazon Web Services (AWS). Learn how to find and access NSIDC DAAC data directly in the cloud.
This short article describes the customization services available for ICESat-2 data using Earthdata Search.