Development of an Atmospheric Carbon Dioxide Standard Gas Saving System and Its Application to a Measurement at a Site in the West Siberian Forest

Observations of the atmospheric CO2 concentration from a 90-m tower in Berezorechka, western Siberia, that have taken place since October 2001 were used to characterize CO2 variations over a vast boreal forest area. A new CO2 standard gas saving system was developed that reduced the consumption of standard gases and kept the analysis precision to within 0.3 mu mol mol(-1). The CO2 day-to-day variation correlated well with atmospheric stability. The average amplitudes of the diurnal variation at 80 m were found to be about 17 and 1.5 mu mol mol(-1) in July and December 2003, respectively. Extremely high daytime CO2 concentrations of greater than 400 mu mol mol(-1) were occasionally observed during the winter, which were caused by anticyclonic atmospheric conditions lasting more than several days. Afternoon CO2 values observed at the 80-m height agreed to within 0.4 mu mol mol(-1) with aircraft CO2 measurements taken in the planetary boundary layer; disagreements were found for anticyclonic conditions in the winter. The afternoon CO2 values reached their maximum in mid-January and their minimum late in July, with the seasonal amplitude of 30.9 mu mol mol(-1). Compared to observations at background stations, this observation tower recorded a larger seasonal amplitude and earlier occurrence of the seasonal minimum.