Performance of a Space-based Methane Lidar
Future space-based lidar measurements of anthropogenic greenhouse gases are expected to close observational gaps particularly over remote, polar, and aerosol-contaminated regions where in-situ and passive remote sensing observation techniques have difficulties. Recently, a “Methane Remote Lidar Miss...
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ftdlr:oai:elib.dlr.de:91814 2023-05-15T13:12:04+02:00 Performance of a Space-based Methane Lidar Kiemle, Christoph Ehret, Gerhard Kawa, S. R. Flamant, Pierre Browell, Edward V. 2014-05-01 http://elib.dlr.de/91814/ http://www.egu.eu unknown Kiemle, Christoph und Ehret, Gerhard und Kawa, S. R. und Flamant, Pierre und Browell, Edward V. (2014) Performance of a Space-based Methane Lidar. In: EGU General Assembly (ISSN: 1474-7065). EGU GA, 28.4.-2.5.14, Wien. ISSN 1474-7065 Lidar Konferenzbeitrag NonPeerReviewed 2014 ftdlr 2017-02-12T23:46:52Z Future space-based lidar measurements of anthropogenic greenhouse gases are expected to close observational gaps particularly over remote, polar, and aerosol-contaminated regions where in-situ and passive remote sensing observation techniques have difficulties. Recently, a “Methane Remote Lidar Mission” (MERLIN) was proposed by DLR and CNES in the frame of a German-French climate monitoring initiative. The goal is to measure atmospheric methane at high precision and unprecedented accuracy sufficient to constrain the various surface sources significantly better than with the current observational network. The MERLIN mission will have a minimum operational lifetime of 3 years. It is currently in Phase B, in which all mission components are planned in detail. Launch is foreseen in 2017. The MERLIN data will primarily be supplied to inverse numerical models that use the globally observed concentration gradients to infer methane surface fluxes. Simulations with an instrument model are used to assess the performance of this mission in terms of random error (measurement precision) with the help of MODIS and CALIPSO satellite observations of earth surface albedo and atmospheric optical depth, respectively. These are key environmental state parameters for integrated path differential absorption (IPDA) lidar which uses the surface backscatter to measure the atmospheric methane column beneath the satellite. Our 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. This applies to monthly aggregated measurement samples within areas of 50x50 km², and approaches the requirements that had been formulated by future users of the data in order to meet the abovementioned goal. Globally, the mean precision for the simulated year 2007 is 1.6 %, with a standard deviation of 0.7 %. In arctic and subarctic regions, 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 %. Conference Object albedo Arctic Ice permafrost Subarctic German Aerospace Center: elib - DLR electronic library Arctic |
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German Aerospace Center: elib - DLR electronic library |
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topic |
Lidar |
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Lidar Kiemle, Christoph Ehret, Gerhard Kawa, S. R. Flamant, Pierre Browell, Edward V. Performance of a Space-based Methane Lidar |
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Lidar |
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Future space-based lidar measurements of anthropogenic greenhouse gases are expected to close observational gaps particularly over remote, polar, and aerosol-contaminated regions where in-situ and passive remote sensing observation techniques have difficulties. Recently, a “Methane Remote Lidar Mission” (MERLIN) was proposed by DLR and CNES in the frame of a German-French climate monitoring initiative. The goal is to measure atmospheric methane at high precision and unprecedented accuracy sufficient to constrain the various surface sources significantly better than with the current observational network. The MERLIN mission will have a minimum operational lifetime of 3 years. It is currently in Phase B, in which all mission components are planned in detail. Launch is foreseen in 2017. The MERLIN data will primarily be supplied to inverse numerical models that use the globally observed concentration gradients to infer methane surface fluxes. Simulations with an instrument model are used to assess the performance of this mission in terms of random error (measurement precision) with the help of MODIS and CALIPSO satellite observations of earth surface albedo and atmospheric optical depth, respectively. These are key environmental state parameters for integrated path differential absorption (IPDA) lidar which uses the surface backscatter to measure the atmospheric methane column beneath the satellite. Our 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. This applies to monthly aggregated measurement samples within areas of 50x50 km², and approaches the requirements that had been formulated by future users of the data in order to meet the abovementioned goal. Globally, the mean precision for the simulated year 2007 is 1.6 %, with a standard deviation of 0.7 %. In arctic and subarctic regions, 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 %. |
format |
Conference Object |
author |
Kiemle, Christoph Ehret, Gerhard Kawa, S. R. Flamant, Pierre Browell, Edward V. |
author_facet |
Kiemle, Christoph Ehret, Gerhard Kawa, S. R. Flamant, Pierre Browell, Edward V. |
author_sort |
Kiemle, Christoph |
title |
Performance of a Space-based Methane Lidar |
title_short |
Performance of a Space-based Methane Lidar |
title_full |
Performance of a Space-based Methane Lidar |
title_fullStr |
Performance of a Space-based Methane Lidar |
title_full_unstemmed |
Performance of a Space-based Methane Lidar |
title_sort |
performance of a space-based methane lidar |
publishDate |
2014 |
url |
http://elib.dlr.de/91814/ http://www.egu.eu |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
albedo Arctic Ice permafrost Subarctic |
genre_facet |
albedo Arctic Ice permafrost Subarctic |
op_relation |
Kiemle, Christoph und Ehret, Gerhard und Kawa, S. R. und Flamant, Pierre und Browell, Edward V. (2014) Performance of a Space-based Methane Lidar. In: EGU General Assembly (ISSN: 1474-7065). EGU GA, 28.4.-2.5.14, Wien. ISSN 1474-7065 |
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1766250193804591104 |