Multi-Channel Ice Penetrating Radar Traverse for Estimates of Firn Density in the Percolation Zone, Western Greenland Ice Sheet, Meehan, Tate, Bradford John, Marshall H.P., Osterberg Erich, Hawley Bob, Hawley Bob, Overly Thomas, Lewis Gabe, Graeter Karina, and McCarthy Forrest , 85th Annual Western Snow Conference, 2017, Boise, Idaho, (2017)