• On Wednesday, June 12 from 9:00 a.m. to 12:00 p.m. (US Mountain Time), the following data collections may not be available due to a planned system maintenance: ASO, AMSR Unified, AMSR-E, Aquarius, High Mountain Asia, IceBridge, ICESat/GLAS, ICESat-2, LVIS, MEaSUREs, MODIS, Nimbus, SMAP, SnowEx, SSM/I-SSMIS and VIIRS. Users of the SMAP near real-time products should use the NASA LANCE HTTPS File System for data access. 

  • The ICESat-2 Quick Look data sets are currently experiencing delays beyond the nominal 3-day latency. High solar activity caused ICESat-2 to enter Safe Mode, leading to delays and data gaps. Recovery of the system is expected to start on 16 May 2024 and will take several days to complete. We apologize for any inconvenience this may cause.

ATLAS/ICESat-2 L3A Calibrated Backscatter Profiles and Atmospheric Layer Characteristics Quick Look, Version 6
Data set id:
DOI: 10.5067/ATLAS/ATL09QL.006
This is the most recent version of these data.
Version Summary
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


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.
Data Format(s):
Temporal Coverage:
28 December 2023 to present
Temporal Resolution:
  • 91 day
Spatial Resolution:
  • Not Specified
Spatial Reference System(s):
WGS 84
Spatial Coverage:
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.

Data Access & Tools

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

Help Articles

General Questions & FAQs

Read this help article to learn about what ICESat-2 quick look data products are and how to find them.
This short article describes the customization services available for ICESat-2 data using Earthdata Search.