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

  • Revision 1 data files from 10 August 2022 to 12 October 2022 have been removed due to a processing error and are now replaced by revision 2 files.

ATLAS/ICESat-2 L3A Calibrated Backscatter Profiles and Atmospheric Layer Characteristics, Version 5 (ATL09)
Data set:
ATL09
This is the most recent version of these data.
Version Summary
Changes for this version include:

  • Added new routine process_blow_snow_dens to compute blowing snow height and diamond dust heights based on methods defined in the Density Dimension Algorithm (DDA) ATBD. bsnow_h_dens now has valid values when the DDA detects blowing snow.

  • Added constants bs_quartile, bs_gap, bs_bin_thresh, dd_min_top_bin, dd_bin_thresh, bs_thresh_sens, bs_thresh_bias, bs_downsample, bs_thresh_seg_len to ATL09.

  • Added parameters bsnow_dens_flag, ddust_htop_dens, ddust_hbot_dens to ATL09.

  • Added parameter podppd_flag to ATL09. podppd_flag provides identification of ATLAS data in nominal geolocation quality status or a degraded quality. podppd_flag =0 means geolocation is in reference ground track pointing with normal quality. podppd_flag =4 means geolocation is in around-the-world scan or ocean scan with normal quality. Other values are degraded quality.

  • Set Fill Value to 127 for snow_ice on ATL09.

  • Density Dimension Algorithm (DDA) processing is now done on same solar elevation sub-chunks (day, night, twilight) rather than using the first solar elevation per processing chunk.

  • Added check on invalid aclr_true and raised limit of aclr_clim to prevent errors.

  • Changed dead time correction algorithm used to correct the surface signal magnitude. This should improve the accuracy of the parameter surface_sig. This improved Apparent Surface Reflectivity (ASR) accuracy.

  • Replaced ANC32 surface reflectance map based on GOME with one generated from actual ICESat-2 ASR measurements in clear (no cloud or aerosol layers) conditions. This should increase the accuracy of ASR-based cloud detection and column optical depth measurements.

Overview

This data set (ATL09) contains calibrated, attenuated backscatter profiles, layer integrated attenuated backscatter, and other parameters including cloud layer height and atmospheric characteristics obtained from the data. 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):
CLOUD PROPERTIES LIDAR BACKSCATTER
Platform(s):
ICESat-2
Sensor(s):
ATLAS
Data Format(s):
HDF5
Temporal Coverage:
13 October 2018 to present
Temporal Resolution:
91 day
Spatial Resolution:
280 m
Spatial Coverage:
N:
90
S:
-90
E:
180
W:
-180

Data Access & Tools

A free NASA Earthdata Login account is required to access these data. Learn More

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.