Mathilde Simeon has more than 8 years of experience in the domain of passive observation of the earth. After a master’s degree in Astrophysics at the Science and Engineering University of Toulouse, she has improved dust aerosol charaterization while working with IASI infrared dataset. Since seven years, she works as radiometry expert at CLS, on ESA and CNES projects, performing instrument processing, assessment and studies. She developed her experience in instrument monitoring with Jason3, ALtiKa and Sentinel-3 missions, and simulation with the development of end to end simulators for ICARO and CoastRad projects.