1. The greenhouse gases observing satellite (GOSAT) project. http://www.gosat.nies.go.jp
2. Network for the detection of atmospheric composition change (NDACC), http://ndaccdemo.org/
3. The total carbon column observing network;Wunch;Philos Trans R Soc A Math Phys Eng Sci,2011
4. TROPOMI Data Products. Methane. http://www.tropomi.eu/data-products/methane
5. Quarterly validation report of the Copernicus sentinel-5 precursor operational data products#05:April 2018 –November 2019. S5P MPC Routine Operations Consolidated Validation Report (ROCVR)/ S5P-MPC-IASB-ROCVR-05.0.1-20191217. #05version 05.0.12019-12-17. Editors: J.-C. Lambert, A. Keppens, D. Hubert, and B. Langerock