ICESat-2 Level-1 Products

Image: NASA Goddard Space Flight Center.

Reformatted Telemetry (ATL01)

Raw ATLAS/ICESat-2 data are decompressed, ordered in time, and reformatted to HDF5. ATL01 consists of all the ICESat-2 data downlinked by the X-band telemetry stream, in a bit-decompressed, time-aligned, product.

ATL01 contains all the pertinent information related to:

  • altimetry
  • the atmosphere
  • the laser reference system
  • housekeeping data
  • calibration mode
  • spacecraft ancillary science data

ATL01 is generated as input for the Level 1B product and for use by researchers who require ATLAS/ICESat-2 data at the lowest possible level.

Image: NASA Goddard Space Flight Center.

Science Unit Converted Telemetry (ATL02)

ATLAS/ICESat-2 Level 1B processing applies instrument corrections to the ATL01 data, such as removing biases in timing and pointing measurements and correcting for the effects of temperature and voltage variations on the ATLAS electronics.

The primary function of ATL02 is to: 

  • Record radiometric parameters for system–level, quality control analysis
  • Support the Precise Pointing Determination (PPD) and the Precise Orbit Determination (POD) processing
  • Provide source data for the Level-2 global geolocated photons product (ATL03) 
  • Provide raw atmospheric profiles for each strong beam to the Level-2 normalized relative backscatter product (ATL04)