Simulation of CO2 variations at Chinese background atmospheric monitoring stations between 2000 and 2009: Applying a CarbonTracker model

We carried out a downscaling treatment over China using the CarbonTracker numerical model, which was applied using double grid nesting technology (3° × 2° over the whole globe, 1° × 1° over China), simulating and analyzing atmospheric CO₂ concentrations over 10 recent years (2000–2009). The simulation results agreed very well with observed data from four background atmospheric monitoring stations in China (The periods for which the simulation results and observed values be compared were January 2000 to December 2009 for the WLG station and June 2006 to December 2009 for the SDZ, LFS, and LAN stations), giving correlation coefficients of >0.7. The high-resolution simulation data correlated slightly better than the low resolution simulation data with the observed data for three of the regions’ atmospheric background stations. Further analysis of the annual, seasonal CO₂ concentration variations at the background stations showed that the CO₂ concentration increased each year over the study period, with an average annual increase of more than 5%, and annual increases of more than 7% at the Shangdianzi and Lin’an stations. Seasonal CO₂ variations were greater at the Longfengshan station than at the Shangdianzi or Lin’an stations. However, the CO₂ concentrations were higher at the Shangdianzi and Lin’an stations because they are greatly affected by human activities in the Jingjinji and Changjiang Delta economic zones. Spatial distribution in CO₂ concentrations and fluxes were higher in eastern than in western China.