Characterizing Surface Properties using NASA Operation IceBridge ATM Waveform Data

The Airborne Topographic Mapper (ATM) measures surface elevation using a conical scanning 532 nm laser. Beginning with NASA Operation IceBridge campaigns flown in mid-2017, full waveforms of transmitted and returned ATM laser pulses have been made publicly available through the National Snow and Ice Data Center (NSIDC), allowing for a more detailed analysis of the geophysical surface properties that modify laser pulses returning from target surfaces. Characterizing surface properties directly from ATM laser returns holds the promise to provide information at higher spatial resolutions than many satellite observations and allow for surface characterization in the absence of coincident visible and near-infrared satellite observations.

In this study, we fit exponentially-modified Gaussian functions to ATM waveforms collected on Operation IceBridge flights in July 2017 to quantify symmetric and asymmetric changes to received waveforms. We combine ATM waveform data with near-coincident ice surface temperatures derived from MODIS and coincident visible imagery from the Digital Mapping System (DMS) to identify the effect of geophysical properties such as melting snow, surface roughness, and melt ponds on received ATM waveforms.