MERLIN: a space-based methane monitor

Methaneis a powerfulgreenhouse gas. The radiative forcingcaused by methanecontributes significantly to the warming of the atmosphere. To better understand the complex global MethaneCycle, it is necessary to apply space-based measurements techniques in order to obtain global coverage at high precision The MethaneRemote Sensing LidarMission ( MERLIN) is a joint French-German cooperation on a micro satellite mission for space-based measurement of spatial and temporal gradients of atmospheric methanecolumns on a global scale. MERLINwill be the first Integrated Path Differential Absorption LIDARfor methanemonitoring from space. In contrast to passive methanemissions, the LIDARinstrument allows to retrieve methanefluxes at all-latitudes, allseasons and during night as it is not relying on sunlight. First scientific studiesshow a substantial reduction of the prior methaneflux uncertainties in key observational regions when using synthetic MERLINobservations in the flux inversion experiments. Furthermore, MERLINobservations can help to quantify and verify in scientific credible way national emission reduction scenarios as formulated in the Kyoto protocol. This paper reports on the present status of MERLINand gives an overview on the joint mission concept with the German LIDARon the French satellite platform MYRIADE.