Presentation
The German-French (DLR-CNES) MERLIN (MEthane Remote LIdar missioN) satellite will be launched in 2029 to monitor methane atmospheric columns (XCH4) from active measurements by an integrated path differential absorption nadir-viewing Lidar. The high expected accuracy of MERLIN observations (shot-by-shot measurements binned over 50-km along the satellite track) – below 1% for random errors and below 0.2% for systematic errors – should improve our knowledge of methane emissions for most continental regions of the world, including high latitudes thanks to the active dimension of the mission.
Within SATINV, we prepare the exploitation of future MERLIN XCH4 products which will be assimilated into atmospheric transport and chemistry models to infer methane emissions and sinks. In particular, during the development phase of the mission, we assess the theoretical uncertainty reduction on methane emissions thank to OSSEs (Observing System Simulation Experiments), depending on several possible scenarios of instrument characteristics and plausible causes of random and systematic errors.
Example of uncertainty reduction (in %). left) accounting for random observations errors. b/ accounting for both random and systematic (for one scenario) observation errors.. A negative uncertainty reduction indicates regions where systematic errors lead to larger uncertainties than the current uncertainty on surface emissions.
Contacts:
- Philippe Bousquet (mission co-PI):
- Cédric Bacour (OSSE):
- Marielle Saunois (Global Methane Budget):
Related articles:
Ehret, G., Bousquet, P., Pierangelo, C., Alpers, M., Millet, B., Abshire, J., … & Crevoisier, C. (2017). MERLIN: a French-German space lidar mission dedicated to atmospheric methane. Remote Sensing, 9(10), 1052.
Bousquet, P., Pierangelo, C., Bacour, C., Marshall, J., Peylin, P., Ayar, P. V., … & Gibert, F. (2018). Error budget of the Methane Remote LIdar missioN and its impact on the uncertainties of the global methane budget. Journal of Geophysical Research: Atmospheres, 123(20), 11-766.