MERLIN: overview of the design status of the lidar Instrument

Abstract

The Methane Remote Sensing LIDAR Mission (MERLIN) is a joint French-German cooperation on the development, launch and operation of a climate monitoring satellite, executed by the French Space Agency CNES and the German DLR Space Administration. It is focused on global measurements of the spatial and temporal gradients of atmospheric Methane (CH4) with a precision and accuracy sufficient to constrain Methane fluxes significantly better than with the current observation network.Merlin is a LIDAR Instrument using the IPDA principle. This instrument principle relies on the different absorption of the laser signal by atmospheric Methane at two laser wavelengthson-line and off-line -both around 1.645 μm, reflected by the Earth surface or by cloud tops. The attenuation is strong at the on-line wavelength; the off-line "reference" wavelength is selected to be only marginally affected by Methane absorption. Being an active instrument with its own light source, the MERLIN LIDAR Instrument does not have to rely on sun illumination of the observed areas and can therefore continuously operate over the orbit.Airbus DS GmbH was selected by the German DLR Space Administration as the industrial Prime Contractor for the Mission Phase C/D, to build the MERLIN Payload, which is the first realization of such an instrument for space in Europe.This presentation will concentrate on the Architecture and the Design of the MERLIN Payload developed during the ongoing Mission Phase C. Further details of the instrument development status will be shown by an overview of the current hardware and design status of the major subsystems.

Recent developments of space optics at Safran Reosc

“…The joint French-German cooperation Methane Remote Sensing LIDAR Mission (MERLIN) employs an Integrated Path Differential Absorption to measure the spatial and temporal gradients of atmospheric CH4 columns [1], [2] on a global scale The satellite is being developed and operated by both countries in a joint partnership between the French Space Agency CNES and the German Space Administration DLR. A general overview on the MERLIN mission and a detailed description of the overall instrument architecture is given in [3] and [4] respectively.…”

Recent Advances Toward Transparent Methane Emissions Monitoring: A Review

“…Satellite imaging spectrometers aim to address the desire for fine pixel resolution to resolve point sources, while increasing the spectral resolution . Lidar provides coarser active measurements of emissions using its own laser light source, freeing it from sun illumination, and can therefore measure during the day or night . This means satellite Lidar methods using integrated path differential absorption will uniquely provide the ability to measure methane emissions nearer the poles when daylight is limited .…”

“… 94 Lidar provides coarser active measurements of emissions using its own laser light source, freeing it from sun illumination, and can therefore measure during the day or night. 99 This means satellite Lidar methods using integrated path differential absorption will uniquely provide the ability to measure methane emissions nearer the poles when daylight is limited. 44 TIR methods are not restricted by spectral interference and can sample dark sources, but tend to have poor sensitivity of lower tropospheric emissions which can make point source estimation difficult as they often miss plumes at the surface.…”

MERLIN (MEthane Remote sensing LIdar missioN) – heading towards PFM and observation of interesting effects

“…The paper presented here concentrates on the design and hardware status of the MERLIN payload, as well as the latest investigations on the APD Etalon effect. The design and hardware status part of this paper is an update of the paper, which was presented at the ICSO conference in 2018, see reference document [11].…”