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

  • Data from 13 November 2022 to 26 October 2023 in Version 6 of ATL03, ATL04, and their derived products will be reprocessed to ITRF2014. See the Data Announcement for details.

ATLAS/ICESat-2 L3B Daily and Monthly Gridded Sea Ice Freeboard, Version 4
Data set id:
DOI: 10.5067/ATLAS/ATL20.004
This is the most recent version of these data.
Version Summary
-Correct reported longitude values to agree with NSIDC Polar Stereographic projections
-Added grid_mapping attribute to land_mask_map array
-Updated the mean sea surface (MSS) variable description; added mentions of the source of the MSS (which uses CryoSat-2 data) and clarified the use of the tide-free system


ATL20 contains daily and monthly gridded estimates of sea ice freeboard, derived from along-track freeboard estimates in the ATLAS/ICESat-2 L3A Sea Ice Freeboard product (ATL10). Data are gridded at 25 km using the SSM/I Polar Stereographic Projection.
Data Format(s):
Temporal Coverage:
14 October 2018 to present
Temporal Resolution:
  • 1 day
Spatial Resolution:
  • 25 km
  • 25 km
Spatial Reference System(s):
NSIDC Sea Ice Polar Stereographic North

NSIDC Sea Ice Polar Stereographic South
Spatial Coverage:
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.

Data Access & Tools

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Help Articles

General Questions & FAQs

This article covers frequently asked questions about the NASA NSIDC DAAC's Earthdata cloud migration project and what it means to data users.
This short article describes the customization services available for ICESat-2 data using Earthdata Search.

How to Articles

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.
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.