Articles | Volume 16, issue 6
https://doi.org/10.5194/gmd-16-1823-2023
https://doi.org/10.5194/gmd-16-1823-2023
Development and technical paper
 | 
31 Mar 2023
Development and technical paper |  | 31 Mar 2023

Estimation of CH4 emission based on an advanced 4D-LETKF assimilation system

Jagat S. H. Bisht, Prabir K. Patra, Masayuki Takigawa, Takashi Sekiya, Yugo Kanaya, Naoko Saitoh, and Kazuyuki Miyazaki

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Cited articles

Anderson, J. L. and Anderson, S. L.: A Monte Carlo Implementation of the Nonlinear Filtering Problem to Produce Ensemble Assimilations and Forecasts, Mon. Weather Rev., 127, 2741–2758, https://doi.org/10.1175/1520-0493(1999)127<2741:AMCIOT>2.0.CO;2, 1999. 
Baek, S.-J., Hunt, B. R., Kalnay, E., Ott, E., and Szunyogh, I.: Local ensemble Kalman filtering in the presence of model bias, Tellus A, 58, 293–306, https://doi.org/10.1111/j.1600-0870.2006.00178.x, 2006. 
Bisht, J. S. H., Machida, T., Chandra, N., Tsuboi, K., Patra, P. K., Umezawa, T., Niwa, Y., Sawa, Y., Morimoto, S., Nakazawa, T., Saitoh, N., and Takigawa, M.: Seasonal Variations of SF6 , CO2 , CH4, and N2O in the UT/LS Region due to Emissions, Transport, and Chemistry, J. Geophys. Res.-Atmos., 126, e2020JD033541, https://doi.org/10.1029/2020JD033541, 2021. 
Bisht, J. S. H., Patra, P. K., Sekiya, T., and Miyazaki, K.: LETKF: CH4 data assimilation code, including the wrapper script to run the assimilation system, Zenodo [code], https://doi.org/10.5281/zenodo.7127658, 2022a. 
Bisht, J. S. H., Patra, P. K., Takigawa, M., Sekiya, T., Kanaya, Y., Saitoh, N., and Miyazaki, K.: MIROC4-ACTM: Model setup, input and output data for CH4 LETKF (Bisht et al., GMD-D, 2022), Zenodo [data set], https://doi.org/10.5281/zenodo.7098323, 2022b. 
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Short summary
In this study, we estimated CH4 fluxes using an advanced 4D-LETKF method. The system was tested and optimized using observation system simulation experiments (OSSEs), where a known surface emission distribution is retrieved from synthetic observations. The availability of satellite measurements has increased, and there are still many missions focused on greenhouse gas observations that have not yet launched. The technique being referred to has the potential to improve estimates of CH4 fluxes.
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