National Aeronautics and Space Administration

Wallops Flight Facility

Documentation

The Airborne Topographic Mapper (ATM) is a conically-scanning laser altimeter that measures the surface topography of a swath of terrain directly beneath the path of the aircraft.  The figure (below) depicts the ATM in operation measuring a swath of ice in Greenland that has been previously surveyed. ATM surveys can be used for change detection, with laser swaths re-surveyed after a few years, and differences between the two surveys yielding estimates of elevation change during the interim.  Comparison of surveys in 1993-4 and 1998-9 produced the first comprehensive assessment of the mass balance of the Greenland ice sheet (Krabill et al., 1999, 2000).  ATM surveys can also be used for comparison with satellite altimeter measurements for calibration/validation (e.g. Martin et al., 2005) or for determining elevation change.  The ATM has collected high quality topographic data from a wide variety of platforms, including the NASA P3, a Chilean Navy P3, a US Navy P3, the NASA DC8, the NCAR C-130, and a half-dozen Twin Otters.

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Further details can be found in the 2012 NASA Technical Report, “Airborne Topographic Mapper Calibration Procedures and Accuracy Assessment” (NASA/TM-2012-215891).

ATM waveform product user manual