Airborne Two-Micron Double-Pulse IPDA Lidar Validation for Carbon Dioxide Measurements Over Land Tamer F. Refaat, Upendra N. Singh, Jirong Yu, Mulugeta Petros, Ruben Remus and Syed Ismail EPJ Web Conf., 176 (2018) 05001 Published online: 13 April 2018 DOI: 10.1051/epjconf/201817605001