ATLAS/ICESat-2 L2A Normalized Relative Backscatter Profiles, Version 3
Data set id:
ATL04
DOI: 10.5067/ATLAS/ATL04.003
There is a more recent version of these data.
Version Summary
Version Summary
Changes for this version include:
- Implemented a new approach for calibration method 3 and added new constants. The new calibration method computes the calibration factor using the average normalized relative backscatter between 13 km and 11 km continuously for a complete orbit, both day and night, while screening out high values of NRB caused by clouds. This calibration method uses a number of adjustable parameters that are defined and changed by control.
- Implemented the scaling factor alpha (set to 0 in Version 2) for the molecular scattering folding correction as a function of solar angle and PCE (photon counting electronics). The changes to the molecular contribution to the received photon count can be computed from equation 3.15 in the ATBD for ATL04.
- Changed the cal_solar_elev_min and cal_solar_elev_max constants to cal_solar_elev_min = -7 and cal_solar_elev_max = -1. These changes re-define the twilight portion of the orbit for calibration method 3 and improve the data for twilight solar elevations.
- The following parameters were added to ancillary_data/atmosphere/. Each parameter is described in the file metadata and where applicable in the ATBD for ATL04: default_nrb_twilight, min_nrb_twilight, max_nrb_twilight, min_calib_twilight, max_calib_twilight, alpha_day_pce1, alpha_day_pce2, alpha_day_pce3, alpha_night_pce1, alpha_night_pce2, alpha_night_pce3, alpha_twilight_pce1, alpha_twilight_pce2, alpha_twilight_pce3.
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 11 November 2020
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.
Data Access & Tools
This data set has been retired. There is a more recent version of these data.
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
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
Harmony API Quickstart Guide: Customizing NASA NSIDC DAAC data in Earthdata Cloud
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).
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.
All data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) is directly accessible through our HTTPS file system using Wget or curl. This article provides basic command line instructions for accessing data using this method.
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.