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Description

ATL04 contains along-track normalized relative backscatter profiles of the atmosphere. The product includes full 532 nm (14 km) uncalibrated attenuated backscatter profiles at 25 times per second for vertical bins of approximately 30 meters. Calibration coefficient values derived from data within the polar regions are also included. 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.

Version Description

Changes for this version include:
  • Reading dem_h and dem_flag from ANC39 rather than input ANC06 and ANC28 files for processing efficiency.
  • Changed dead time correction algorithm used to correct the surface signal magnitude. This should improve the accuracy of the surface_sig parameter and the too small winter time values over Antarctica..
  • Added the podppd_flag parameter to ATL04. The 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 can or ocean scan with normal quality. Other values are degraded quality. This enables detection of ocean scans and other geolocation problems.
  • Fixed a some bugs including an added constant dtime_max as maximum dead time correction, set Fill Value to 127 for cloud_fold_flag, added checks on beam elevation off by 15 degrees, and added a check on negative dead time correction factor.
  • For consistency a list of constants was updated to match the SIPS overrides. See the user guide or ATBD for more details.

Product Summary

Platforms
ICESat-2
Instruments
ATLAS
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Spatial Resolution
280 Meters
Spatial Reference System(s)
WGS 84 (EPSG:4326)
Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
ORBIT
Temporal Extent
2018-10-13 to 2022-10-13
Temporal Resolution
91 Day
Concept ID
C2153572406-NSIDC_CPRD
Data State
DEPRECATED
Number of Files/Granules
0
Processing Level
2A
Published
Science Keywords
Lidar Backscatter

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Palm, S., Yang, Y., Herzfeld, U., Hancock, D., Barbieri, K., Wimert, J., & the ICESat-2 Science Team. (2021). ATLAS/ICESat-2 L2A Normalized Relative Backscatter Profiles, Version 5 [Dataset]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/ATLAS/ATL04.005 Date Accessed: 2026-06-17

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