Martial Haeffelin is a senior research scientist with 25-year experience in atmospheric remote sensing research. He conducted research on the effect of clouds on the global Earth radiation budget at the NASA Langley Research Center (VA, USA) from 1993-2001. In 2002, he initiated a surface-based atmospheric observation program for CNRS-IPSL, developed a world-class atmospheric observatory located in Ecole polytechnique, and directed this program for 15 years.