Abstract
Abstract. Atmospheric carbon dioxide (CO2) mole fractions were continuously measured from January 2009 to December 2011 at four atmospheric observatories in China using cavity ring-down spectroscopy instruments. The stations are Lin'an (LAN), Longfengshan (LFS), Shangdianzi (SDZ), and Waliguan (WLG), which are regional (LAN, LFS, SDZ) or global (WLG) measurement stations of the World Meteorological Organization's Global Atmosphere Watch program (WMO/GAW). LAN is located near the megacity of Shanghai, in China's economically most developed region. LFS is in a forest and rice production area, close to the city of Harbin in northeastern China. SDZ is located 150 km northeast of Beijing. WLG, hosting the longest record of measured CO2 mole fractions in China, is a high-altitude site in northwestern China recording background CO2 concentration. The CO2 growth rates are 3.7 ± 1.2 ppm yr−1 for LAN, 2.7 ± 0.8 ppm yr−1 for LFS, 3.5 ± 1.6 ppm yr−1 for SDZ, and 2.2 ± 0.8 ppm yr−1 (1σ) for WLG during the period of 2009 to 2011. The highest annual mean CO2 mole fraction of 404.2 ± 3.9 ppm was observed at LAN in 2011. A comprehensive analysis of CO2 variations, their diurnal and seasonal cycles as well as the analysis of the influence of local sources on the CO2 mole fractions allows a characterization of the sampling sites and of the key processes driving the CO2 mole fractions. These data form a basis to improve our understanding of atmospheric CO2 variations in China and the underlying fluxes using atmospheric inversion models.
Highlights
Carbon dioxide (CO2) represents the most important contribution to increased radiative forcing (IPCC, 2007)
The mean value of the difference is 0.1 ± 0.1 ppm for 168 sampling events (336 flasks). This result suggests that National Oceanic and Atmospheric Administration (NOAA) flask and China Meteorological Administration (CMA) in situ measurements at WLG are in good agreement and the CMA calibration and quality control procedures are well implemented without generating systematic biases
Atmospheric CO2 measurements made at four World Meteorological Organization’s Global Atmosphere Watch program (WMO/Global Atmosphere Watch (GAW)) stations in China have been reported
Summary
Carbon dioxide (CO2) represents the most important contribution to increased radiative forcing (IPCC, 2007). In 1994, the station was established as a global World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) measurement site, and was equipped to measure CO2 mole fractions by means of a LI-COR nondispersive infrared (NDIR) analyzer. This instrument produced nearly 14 years of high-quality data, which is the longest continuous atmospheric CO2 record in China (Zhou et al, 2003, 2005, 2006). Here we study the observed CO2 mole fractions at the four stations
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