MABEL photon-counting altimetry data for ICESat-2 simulations

Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) is scheduled to launch in 2016 and will carry the Advanced Topographic Laser Altimeter System (ATLAS), which represents a new approach to space-borne determination of surface elevation. Specifically, ATLAS is a micropulse, multibeam, photon-counting laser altimeter with lower energy, a shorter pulse width, and a higher repetition rate relative to the instrument that was onboard ICESat. Given the new and untested technology associated with ATLAS, an airborne instrument, the Multiple Altimeter Beam Experimental Lidar (MABEL), was developed and deployed to provide data needed for algorithm development and to simulate key elements of this new design. We present an overview of the MABEL instrument, the available datasets, including data collected during three different missions (December 2010, March/April 2011, and September 2011), with three slightly different laser energy, pulse repetition rate, and beam configurations. We also present the various versions of these datasets, including a release scaled to ICESat-2-like signal and noise rates. Finally, we present the plan for further data collection over Greenland, scheduled for April 2012. As the ICESat-2 project is in the design phase, the particular configuration of the ATLAS instrument may change before implementation. However, we expect data from MABEL to be relevant for algorithm development, and modeling verification, as long as ATLAS pursues a photon-counting approach to elevation measurements.