ICESat-2 Simulations and Analysis using Sigma Space MPL Measurements over Greenland

The Sigma Space Micro Pulse Lidar (MPL), a 100 channel photon counting instrument, collected data over the Jacobshavn glacier and fjord and adjacent ice sheet regions in July 2009. Sigma Space preprocessed the data to geolocate it and remove instrument-induced anomalies and the majority of the atmospheric noise, delivering a “signal only” data set containing the x, y, z locations of photons received from the surface. This presentation explains the procedure we used to produce simulated ICESat-2 Advanced Topographic Laser Altimeter System (ATLAS) returns from this data and analyze the projected ATLAS instrument performance over these Greenland regions. ATLAS data sets were simulated by sub sampling the MPL data and then adding realistic ICESat-2 background noise. The current ATLAS instrument design includes 9-beams, grouped in three sets of three beams spanning ~6 km in total width. The ICESat-2 project and Science Definition Team defined a number of design cases, which specify the environmental conditions under which we expect ICESat-2 to collect useful data. These design cases were used to predict the performance of the ATLAS instrument. We used the output of these design cases to define the mean number of signal and background photoelectrons in our simulations to define the locations and number of signal and noise photons per shot. We present a preliminary algorithm from which the ground elevation can be calculated from the simulated data sets and calculate the precision of the retrieved elevations by comparing to elevations calculated from the full rate MPL data. An analysis of the precision and characteristics of the cross track slope knowledge at both the 6km and 100m level and how precisely it will allow us to calculate elevation changes using repeat cycles is also presented.