The LMD has developed a differential absorption lidar called MEDAL (MEthane Differential Absorption Lidar) to measure atmospheric methane profiles. It uses an innovative laser also developed at the laboratory. MEDAL measured its first methane concentration profiles in a horizontal viewing configuration from the École Polytechnique site towards Paris (northward direction). It was thus able to measure the end of the dissipation of a methane plume generated by a fire at a waste treatment plant in Paris in April 2025. The accuracy of the measurements is confirmed by the ICOS station at Saclay.

These results are presented in an AMT article: Edouart, D., Gibert, F., and Cénac, C.: 1.645 µm differential absorption lidar measurements of atmospheric methane using an Er:YAG laser, Atmos. Meas. Tech., 19, 4875–4888, https://doi.org/10.5194/amt-19-4875-2026, 2026.