N: 90 S: -90 E: 180 W: -180
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Description
ATL09QL is the quick look version of ATL09. Once final ATL09 files are available the corresponding ATL09QL files will be removed.
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.
Version Description
Changes for Version 6 are as follows:
- Modified blowing snow detection algorithm to reduce false positive detections often seen in daylight
- Added and modified the blowing snow confidence values (bsnow_con) to include new descriptions and changed the parameter from a one-byte to a two-byte integer value
- Added four values to the layer attribute parameter (layer_attr)
- Added a new parameter called clear air precipitation top height (cap_h) that denotes the top height of clear air precipitation that reached the ground
- Replaced the ANC32 surface reflectance map (now based on three years of ICESat-2 surface reflectance measurements instead of two) to fill in gaps
- Changed bs_quartile to bs_quantile in ATL09 and related code
- Modified code to use density matrix 1 instead of density matrix 2 when computing layer densities
- Implemented a third pass of the density dimension algorithm to reduce the effect of noise in creating false layers
- Updated the ANC45 cloud/aerosol discrimination table to increase the accuracy of detected layers
Product Summary
Platforms
Instruments
Spatial Extent
Spatial Resolution
280 Meters
Spatial Reference System(s)
WGS 84 (EPSG:4326)
Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
ORBIT
Temporal Extent
2023-01-15 to 2025-06-17
Temporal Resolution
91 Day
Concept ID
C3861651478-NSIDC_CPRD
Data State
DEPRECATED
Processing Level
3
Published
Science Keywords
Cloud Properties
,
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.
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Palm, S., Yang, Y., Herzfeld, U., Hancock, D., Barbieri, K., Wimert, J., & Team, T. I. C. E. S.-2 S. (2023). ATLAS/ICESat-2 L3A Calibrated Backscatter Profiles and Atmospheric Layer Characteristics Quick Look, Version 6 [Data set]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/ATLAS/ATL09QL.006 Date Accessed: 2026-05-12
Palm, Steve, Yeukui Yang, Ute Herzfeld, David Hancock, Kristine Barbieri, Jesse Wimert, and The ICESat-2 Science Team. “ATLAS/ICESat-2 L3A Calibrated Backscatter Profiles and Atmospheric Layer Characteristics Quick Look, Version 6.” NASA National Snow and Ice Data Center Distributed Active Archive Center, 2023. doi:10.5067/ATLAS/ATL09QL.006. Date Accessed: 2026-05-12
Palm, Steve, et al. ATLAS/ICESat-2 L3A Calibrated Backscatter Profiles and Atmospheric Layer Characteristics Quick Look, Version 6. NASA National Snow and Ice Data Center Distributed Active Archive Center, 2023, doi:10.5067/ATLAS/ATL09QL.006. Date Accessed: 2026-05-12
TABLE OF CONTENTS