MERLIN: A French-German Space Lidar Mission Dedicated to Atmospheric Methane

• Main Authors: Gerhard Ehret, Philippe Bousquet, Clémence Pierangelo, Matthias Alpers, Bruno Millet, James B. Abshire, Heinrich Bovensmann, John P. Burrows, Frédéric Chevallier, Philippe Ciais, Cyril Crevoisier, Andreas Fix, Pierre Flamant, Christian Frankenberg, Fabien Gibert, Birgit Heim, Martin Heimann, Sander Houweling, Hans W. Hubberten, Patrick Jöckel, Kathy Law, Alexander Löw, Julia Marshall, Anna Agusti-Panareda, Sebastien Payan, Catherine Prigent, Patrick Rairoux, Torsten Sachs, Marko Scholze, Martin Wirth
• Format: Article
• Language: English
• Published: MDPI AG 2017-10-01
• Series: Remote Sensing
• Subjects: MERLIN; space mission; IPDA Lidar; atmospheric methane; CH4 emissions; global methane budget
• Online Access: https://www.mdpi.com/2072-4292/9/10/1052

The MEthane Remote sensing Lidar missioN (MERLIN) aims at demonstrating the spaceborne active measurement of atmospheric methane, a potent greenhouse gas, based on an Integrated Path Differential Absorption (IPDA) nadir-viewing LIght Detecting and Ranging (Lidar) instrument. MERLIN is a joint French and German space mission, with a launch currently scheduled for the timeframe 2021/22. The German Space Agency (DLR) is responsible for the payload, while the platform (MYRIADE Evolutions product line) is developed by the French Space Agency (CNES). The main scientific objective of MERLIN is the delivery of weighted atmospheric columns of methane dry-air mole fractions for all latitudes throughout the year with systematic errors small enough (<3.7 ppb) to significantly improve our knowledge of methane sources from global to regional scales, with emphasis on poorly accessible regions in the tropics and at high latitudes. This paper presents the MERLIN objectives, describes the methodology and the main characteristics of the payload and of the platform, and proposes a first assessment of the error budget and its translation into expected uncertainty reduction of methane surface emissions.