Modeling the atmospheric transport of CO2
Spatial and temporal distribution and variability of the atmospheric CO2 concentration in Europe and Western Siberia is investigated using the regional atmospheric model REMO. In REMO transport of CO2 and other tracers is simulated on-line together with the meteorology, offering a consistent way to describe subgrid scale transport processes (Langmann, 2000).
In the model simulations the spatial and temporal distributions of CO2 fluxes at the earth surface are prescribed as lower boundary conditions:
1.Uptake and release of CO2 by vegetation and soil is described by simulations of terrestrial biosphere models, e.g. TURC (Lafont et al., 2002) or BIOME-BGC (Churkina et al., 2004)
2.Anthropogenic CO2 emissions are prescribed from the Emission Database for Global Atmospheric Research EDGAR (Olivier et al., 1996).
3.Exchange of CO2 at the ocean surface is taken from the dataset of Takahashi et al. (1999).
In order to take into account the influences of long-term variations and sources and sinks outside the model domain, results from the coarser grid global transport model TM3 (Heimann and Körner, 2003) are used as initial and boundary conditions in the REMO simulations. Comparisons to aircraft and surface measurements of CO2 at stations in Europe and Russia show that the model is able to realistically predict the temporal variability and the vertical structure of the CO2 concentration at these stations (Chevillard et al, 2002).
The monthly mean CO2 concentration in the boundary layer (at 300 m) for July 1998 is shown in Figure 1. In summer, the CO2 concentration over Siberia is significantly lower due to the photosynthetic uptake by the biosphere. The strong regional influence of the anthropogenic emissions in Europe is also evident in the spatial pattern.
Figure 1: Monthly mean CO2 concentration at 300m in July 1998
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