Performance simulations for a spaceborne methane lidar mission

• Published in: Journal of geophysical research. Atmospheres 2014-04, Vol.119 (7), p.4365-4379
• Main Authors: Kiemle, C., Kawa, S. R., Quatrevalet, M., Browell, E. V.
• Format: Article
• Language: English
• Subjects: Aerosols; Albedo; Anthropogenic factors; atmospheric methane; Atmospherics; Climate monitoring; Earth orbits; Geophysics; Greenhouse gases; Lidar; MERLIN; Methane; Missions; Optical analysis; Performance assessment; Permafrost; Population density; Reflectance; Reflectivity; Remote sensing; Simulation; Snow; spaceborne IPDA lidar
• ISSN: 2169-897X; 2169-8996
• DOI: 10.1002/2013JD021253

Future spaceborne lidar measurements of key anthropogenic greenhouse gases are expected to close current observational gaps particularly over remote, polar, and aerosol‐contaminated regions, where actual in situ and passive remote sensing observation techniques have difficulties. For methane, a “Methane Remote Lidar Mission” was proposed by Deutsches Zentrum für Luft‐ und Raumfahrt and Centre National d'Etudes Spatiales in the frame of a German‐French climate monitoring initiative. Simulations assess the performance of this mission with the help of Moderate Resolution Imaging Spectroradiometer and Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations of the earth's surface albedo and atmospheric optical depth. These are key environmental parameters for integrated path differential absorption lidar which uses the surface backscatter to measure the total atmospheric methane column. Results show that a lidar with an average optical power of 0.45 W at 1.6 µm wavelength and a telescope diameter of 0.55 m, installed on a low Earth orbit platform (506 km), will measure methane columns at precisions of 1.2%, 1.7%, and 2.1% over land, water, and snow or ice surfaces, respectively, for monthly aggregated measurement samples within areas of 50 × 50 km2. Globally, the mean precision for the simulated year 2007 is 1.6%, with a standard deviation of 0.7%. At high latitudes, a lower reflectance due to snow and ice is compensated by denser measurements, owing to the orbital pattern. Over key methane source regions such as densely populated areas, boreal and tropical wetlands, or permafrost, our simulations show that the measurement precision will be between 1 and 2%. Key Points Global patterns in a spaceborne methane IPDA lidar's precision are assessedCALIPSO and MODIS data are used for optical depth and ground reflectanceThe precision over 50 × 50 km2 is 1% to 2% for key methane source regions