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. He is currently the Deputy Director of Institut Pierre Simon Laplace, in charge of Earth Observations, and acts as scientific director of ACTRIS-FR a French research infrastructure dedicated to support climate research. Dr. Haeffelin conducts research on cloud physical processes and remote sensing, as well as cloud effects on the solar resource for photovoltaic energy production. He is the author and co-author of more than 80 peer-reviewed articles.