ATLAS/ICESat-2 L3A Ocean Surface Height, Version 2
Data set id:
ATL12
DOI: 10.5067/ATLAS/ATL12.002
There is a more recent version of these data.
Version Summary
Version Summary
Changes for this version include:
- The bckgrd_rate parameter (/gt[x]/ssh_segments/stats/) is now read from ATL03 and the mean value for signal photons is written to ATL12 as /gt[x]/ssh_segments/stats/backgr_seg.
- The input photon arrays used to estimate sea state bias (x, height, time, ocean-segment, and histogram-bin-index/signal-photon-mask) are now sorted by along-track x.
- All data with heights greater than the shore depth (default = -10 m) are not processed as ocean to ensure ocean processing doesn't occur over land.
- Changed the processing code and ATL12 template to allow invalid values for significant wave height (/gt[x]/ssh_segments/heights/swh) and sea state bias (/gtx/ssh_segments/heights/bin_ssbias).
- Fixed errors that caused segments to be skipped after long gaps and along the boundary between two orbits.
- Updated parameter name "ds_y_bins" to "ds_y_bincenters" in the ATL12 product to be consistent with the ATBD and developmental code.
- Changed the ocean histogram bin center height edges to eliminate a 0.5 cm ambiguity in histogram statistics.
- Corrected the order in which surface types are listed on the surf_type_prcnt parameter description.
- Added an ocean photon selection, boxcar smoothing parameter (/ancillary_data/ocean/pts2bin) and assigned it a default value of 21. This value can be overridden in the control file.
- Made code updates to modify which residual histogram bins are selected for use. The code now includes a second-pass threshold test based on histogram far tails.
- Added a tide_equilibrium_seg parameter in /gt[x]/ssh_segments/stats that is the mean of the ATL03 equilibrium tide values for signal photons.
- Updated the SNRc calculation to use the same process as the deconvolution noise filtering.
- Shifted the TEP bin center heights to match the fine histogram bin center heights. This allows for better alignment of the surface histogram after Weiner deconvolution of the impulse response.
Overview
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.
Parameter(s):
SEA SURFACE HEIGHT
Platform(s):
ICESat-2
Sensor(s):
ATLAS
Data Format(s):
HDF5
Temporal Coverage:
13 October 2018 to 15 November 2019
Temporal Resolution:
- 91 day
Spatial Resolution:
- Not Specified
Spatial Reference System(s):
WGS 84
EPSG:4326
Spatial Coverage:
N:
90
S:
-90
E:
180
W:
-180
Blue outlined 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.
Documentation
User Guide
ATBDs
General Resources
Product Specification Documents
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
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
Harmony API Quickstart Guide: Customizing NASA NSIDC DAAC data in Earthdata Cloud
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.
Learn the basic steps for using OpenAltimetry to browse and download ICESat-2 data products.
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).
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.
All data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) is directly accessible through our HTTPS file system using Wget or curl. This article provides basic command line instructions for accessing data using this method.
This article highlights the NSIDC DAAC data sets available with customization options and outlines a workflow for searching, ordering, and customizing data in NASA Earthdata Search. This approach is ideal for users who want to download data to their local machine.
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.