High-resolution inverse modelling of European CH4 emissions using the novel FLEXPART-COSMO TM5 4DVAR inverse modelling system

We present a novel high-resolution inverse modelling system (“FLEXVAR”) based on FLEXPARTCOSMO back trajectories driven by COSMO meteorological fields at 7 km×7 km resolution over the European COSMO-7 domain and the four-dimensional variational (4DVAR) data assimilation technique. FLEXVAR is coupled offline with the global inverse modelling system TM5-4DVAR to provide background mole fractions (“baselines”) consistent with the global observations assimilated in TM5-4DVAR. We have applied the FLEXVAR system for the inverse modelling of European CH4 emissions in 2018 using 24 stations with in situ measurements, complemented with data from five stations with discrete air sampling (and additional stations outside the European COSMO-7 domain used for the global TM5-4DVAR inversions). The sensitivity of the FLEXVAR inversions to different approaches to calculate the baselines, different parameterizations of the model representation error, different settings of the prior error covariance parameters, different prior inventories, and different observation data sets are investigated in detail. Furthermore, the FLEXVAR inversions are compared to inversions with the FLEXPART extended Kalman filter (“FLExKF”) system and with TM5-4DVAR inversions at 1 ◦ ×1 ◦ resolution over Europe. In contrast, the top-down estimates for the sum of emissions from the UK and Ireland agree relatively well with the total of anthropogenic and natural bottom-up inventories.

BERGAMASCHI Peter;  SEGERS Arjo;  BRUNNER Dominik;  HAUSSAIRE Jean-Matthieu;  HENNE S;  RAMONET Michel;  ARNOLD Tim;  BIERMANN Tobias;  CHEN Huilin;  CONIL Sebastien;  DELMOTTE Marc;  FORSTER Grant;  FRUMAU A;  KUBISTIN Dagmar;  LAN Xin;  LEUENBERGER Markus;  LINDAUER Matthias;  LOPEZ Morgan;  MANCA Giovanni;  MÜLLER-WILLIAMS Jennifer;  O'DOHERTY Simon;  SCHEEREN Bert;  STEINBACHER Martin;  TRISOLINO Pamela;  VITKOVA Gabriela;  YVER-KWOK Camille; 

2022-11-18

COPERNICUS GESELLSCHAFT MBH

JRC128390

1680-7316 (online),   

https://acp.copernicus.org/articles/22/13243/2022/,    https://publications.jrc.ec.europa.eu/repository/handle/JRC128390,   

10.5194/acp-22-13243-2022 (online),