ATLAS/ICESat-2 L2A Normalized Relative Backscatter Profiles, Version 6
Data set id:
ATL04
DOI: 10.5067/ATLAS/ATL04.006
This is the most recent version of these data.
Version Summary
Version Summary
Changes for Version 6 include:
- Added and modified alpha correction constants to improve calibration in the South Atlantic Anomaly (SAA) area.
- Slightly modified the boundaries of the SAA box.
Overview
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.
Parameter(s):
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:
- 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.
Strengths and Limitations
Strengths
- This is an L2A product that contains the normalized relative backscatter (NRB) profiles from the surface to 14 km with 30 m vertical and 280 m horizontal resolutions.
- From the NRB, the raw signal can be computed by adding the background and dividing by the square of the range from the satellite to the bin.
- Using the molecular backscatter profiles from the surface to 20 km with a 30 m vertical resolution and the NRB, the system calibration constant can be computed.
- The product contains 2 and 10 m temperature and wind velocity, as well as vertical profiles of temperature, relative humidity, and pressure.
Limitations
- The NRB profiles span a limited height range: from the surface to 14 km altitude.
- Backscatter (clouds/aerosol) at altitude h, where h > 15 km, is folded down and added to the backscatter present at an altitude of h - 15 km (Palm et al., 2021).
- The signal between 14 and 15 km is not downlinked.
- Daytime signal to noise is low due to solar background noise.
- Because of the limited profile length and folding, daytime background is difficult to compute. This can ultimately affect the ability to accurately calibrate the signal (Palm et al., 2021).
Data Access & Tools
A free NASA Earthdata Login account is required to access these data. Learn More
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
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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.