Articles | Volume 5, issue 1
Geosci. Model Dev., 5, 231–243, 2012
Geosci. Model Dev., 5, 231–243, 2012

Development and technical paper 15 Feb 2012

Development and technical paper | 15 Feb 2012

A global coupled Eulerian-Lagrangian model and 1 × 1 km CO2 surface flux dataset for high-resolution atmospheric CO2 transport simulations

A. Ganshin1, T. Oda2,*, M. Saito2,**, S. Maksyutov2, V. Valsala2,***, R. J. Andres3, R. E. Fisher4, D. Lowry4, A. Lukyanov1, H. Matsueda5, E. G. Nisbet4, M. Rigby6, Y. Sawa5, R. Toumi7, K. Tsuboi5, A. Varlagin8,9, and R. Zhuravlev1 A. Ganshin et al.
  • 1Central Aerological Observatory, Dolgoprudny, Russia
  • 2Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Japan
  • 3Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, USA
  • 4Department of Earth Sciences, Royal Holloway, University of London, London, UK
  • 5Meteorological Research Institute, Tsukuba, Japan
  • 6School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
  • 7Department of Physics, Imperial Collage London, London, UK
  • 8A.N. Severtsov Institute of Ecology and Evolution, Russia
  • 9Russian State Agrarian University – Moscow Timiryazev Agricultural Academy, Russia
  • *now at: Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, USA/National Oceanic and Atmosphere Administration, Earth System Research Laboratory, Boulder, USA
  • **now at: LSCE, Gif Sur Yvette, France
  • ***now at: CAT/ESSC, Indian Institute of Tropical Meteorology, Pune, India

Abstract. We designed a method to simulate atmospheric CO2 concentrations at several continuous observation sites around the globe using surface fluxes at a very high spatial resolution. The simulations presented in this study were performed using the Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA), comprising a Lagrangian particle dispersion model coupled to a global atmospheric tracer transport model with prescribed global surface CO2 flux maps at a 1 × 1 km resolution. The surface fluxes used in the simulations were prepared by assembling the individual components of terrestrial, oceanic and fossil fuel CO2 fluxes. This experimental setup (i.e. a transport model running at a medium resolution, coupled to a high-resolution Lagrangian particle dispersion model together with global surface fluxes at a very high resolution), which was designed to represent high-frequency variations in atmospheric CO2 concentration, has not been reported at a global scale previously. Two sensitivity experiments were performed: (a) using the global transport model without coupling to the Lagrangian dispersion model, and (b) using the coupled model with a reduced resolution of surface fluxes, in order to evaluate the performance of Eulerian-Lagrangian coupling and the role of high-resolution fluxes in simulating high-frequency variations in atmospheric CO2 concentrations. A correlation analysis between observed and simulated atmospheric CO2 concentrations at selected locations revealed that the inclusion of both Eulerian-Lagrangian coupling and high-resolution fluxes improves the high-frequency simulations of the model. The results highlight the potential of a coupled Eulerian-Lagrangian model in simulating high-frequency atmospheric CO2 concentrations at many locations worldwide. The model performs well in representing observations of atmospheric CO2 concentrations at high spatial and temporal resolutions, especially for coastal sites and sites located close to sources of large anthropogenic emissions. While this study focused on simulations of CO2 concentrations, the model could be used for other atmospheric compounds with known estimated emissions.