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

Abstract

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 ?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 ?mol mol?1 in July and December 2003, respectively. Extremely high daytime CO2 concentrations of greater than 400 ?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 ?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 ?mol mol?1. Compared to observations at background stations, this observation tower recorded a larger seasonal amplitude and earlier occurrence of the seasonal minimum.