Temporal and spatial variations of the atmospheric CO2 concentration in China

In order to understand the variations of atmospheric greenhouse gases over the Chinese mainland, an air sampling network was established in March 2003 that included one GAW global station, three GAW regional stations and three cooperative stations. Flask air samples were taken every week at the stations for 3 years. The secular increase and the seasonal variation in the CO2 concentration are clearly observable at all the stations, reflecting global as well as the regional terrestrial biospheric and human activities, as well as the local meteorological conditions. The average CO2 concentration depends on the station, with the lowest value observed at Mt. Waliguan and relatively high values observed at Fukang and Lin-an stations, located in the westernmost and eastern parts of China, respectively. The observed CO2 concentration variations are also discussed within the context of forward transport model simulations using CO2 fluxes derived by time-dependent inversion.