Japan Geoscience Union Meeting 2019

Presentation information

[E] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-CG Complex & General

[A-CG34] Satellite Earth Environment Observation

Thu. May 30, 2019 3:30 PM - 5:00 PM 302 (3F)

convener:Riko Oki(Japan Aerospace Exploration Agency), Yoshiaki HONDA(Center for Environmental Remote Sensing, Chiba University), Yukari Takayabu(Atmosphere and Ocean Research Institute, the University of Tokyo), Tsuneo Matsunaga(Center for Global Environmental Research and Satellite Observation Center, National Institute for Environmental Studies), Chairperson:Tsuneo Matsunaga

3:45 PM - 4:00 PM

[ACG34-20] Estimating regional anthropogenic methane emissions with GOSAT satellite retrievals and ground-based observations

*Shamil Maksyutov1, Aki Tsuruta2, Rajesh Janardanan1, Fenjuan Wang1, Akihiko Ito1, Motoki Sasakawa1, Toshinobu Machida1, Isamu Morino1, Yukio Yoshida1, Johannes Kaiser3, Greet Janssens-Maenhout4, Ed Dlugokencky5, Tsuneo Matsunaga1 (1.National Institute for Environmental Studies, 2.Finnish Meteorological Institute, 3.Deutscher Wetterdienst, 4.European Commission, Joint Research Centre , 5.National Oceanic and Atmospheric Administration, Global Monitoring Division)

Keywords:methane , inverse model, GOSAT, anthropogenic emissions

GOSAT satellite observations of methane are being used for regional and national methane emission estimates in a number of studies using either high resolution regional inverse models or global medium resolution models. We perform global high-resolution methane flux inversion to estimate global methane emissions using atmospheric methane data collected at global in-situ network, which is archived at WDCGG and NIES, and GOSAT satellite retrievals. High resolution tracer transport is implemented by coupling Lagrangian model FLEXPART to a global atmospheric tracer transport model (NIES-TM) and its adjoint. Prior fluxes at 0.1° resolution were prepared for anthropogenic emissions (EDGAR 4.3.2), biomass burning (GFAS), and wetlands (VISIT). The inverse model based on NIES-TM-FLEXPART applies variational optimization to two categories of fluxes: anthropogenic and natural (wetlands). Bi-weekly emissions are estimated for years 2009 to 2017. To reduce GOSAT retrieval biases, the monthly mean difference between GOSAT data and the inversion-optimized forward simulation is estimated for each 5° latitude band and it is subtracted from GOSAT retrievals (NIES Level 2 retrievals, v. 02.72) before including them in the inversion. The bias correction is designed to remove large scale biases in GOSAT retrievals, while retaining local scale variability that contains most information on anthropogenic emissions from intense sources such as megacities. Estimated anthropogenic emissions over large regions (US, China, India) are compared to GCP-CH4 top-down estimates. The sensitivity of the estimated emissions to prior fluxes is tested by adjusting the prior fluxes to match UNFCCC reports for selected large countries.