MERLIN (Methane Remote Sensing Lidar Mission): an Overview

¹ Centre National d’Etudes Spatiales (CNES), 18 Av. E. Belin, 31401 Toulouse, FRANCE
² Centre National d’Etudes Spatiales (CNES), 2 place Maurice Quentin, 75039 Paris, FRANCE
³ Deutsches Zentrum für Luft-und Raumfahrt (DLR), Königswinterer Str. 522-524, 53227 Bonn, GERMANY
⁴ Deutsches Zentrum für Luft-und Raumfahrt (DLR), Münchener Straße 20, 82234 Weßling, GERMANY
⁵ Laboratoire de Météorologie Dynamique (LMD), Ecole Polytechnique, 91128 Palaiseau, FRANCE
⁶ Laboratoire des Sciences du Climat et de l’Environnement (LSCE) 91198 Gif-sur-Yvette, FRANCE

^* Email: clemence.pierangelo@cnes.fr
^** Email: bruno.millet@cnes.fr

Published online: 7 June 2016

Abstract

The Methane Remote Sensing Lidar Mission (MERLIN), currently in phase B, is a joint cooperation between France and Germany on the development, launch and operation of a methane (CH4) monitoring satellite. MERLIN is focused on global measurements of the spatial and temporal gradients of atmospheric CH4, the second most anthropogenic gas, with a precision and accuracy sufficient to constrain Methane fluxes significantly better than with the current observation network.

For the first time, measurements of atmospheric composition will be performed from space thanks to an IPDA (Integrated Path Differential Absorption) LIDAR (Light Detecting And Ranging). This payload is under the responsibility of the German space agency (DLR), while the platform (MYRIADE Evolutions product line) is developed by the French space agency (CNES). The IPDA technique relies on DIAL (Differential Absorption LIDAR) measurements using a pulsed laser emitting at two wavelengths, one wavelength accurately locked on a spectral feature of the methane absorption line, and the other wavelength free from absorption to be used as reference. This technique enables measurements in all seasons, at all latitudes. It also guarantees almost no contamination by aerosols or water vapour cross-sensitivity, and thus has the advantage of an extremely low level of systematic error on the dry-air column mixing ratio of CH4.