Variation of CO2 mole fraction in the lower free troposphere, in the boundary layer and at the surface

L. Haszpra, M. Ramonet, M. Schmidt, Z. Barcza, Z. Pátkai, K. Tarczay, C. Yver, J. Tarniewicz, P. Ciais
2012 Atmospheric Chemistry and Physics Discussions  
Eight years of occasional flask air sampling and 3 years of frequent in situ measurements of carbon dioxide (CO 2 ) vertical profiles on board of a small aircraft, over a tall tower greenhouse gases monitoring site in Hungary are used for the analysis of the variations of vertical profile of CO 2 mole fraction. Using the airborne vertical profiles and the measurements along the 115 m tall tower it is shown that the measurements at the top of the tower estimate the mean boundary layer CO 2 mole
more » ... raction during the mid-afternoon fairly well, with an underestimation of 0.27-0.85 µmol mol −1 in summer, and an overestimation of 0.66-1.83 µmol mol −1 in winter. The seasonal cycle of CO 2 mole fraction is damped with elevation. While the amplitude of the seasonal cycle is 28.5 µmol mol −1 at 10 m above the ground, it is only 10.7 µmol mol −1 in the layer of 2500-3000 m corresponding to the lower free atmosphere above the well-mixed boundary layer. The maximum mole fraction in the layer of 2500-3000 m can be observed around 25 March on average, two weeks ahead of that of the marine boundary layer reference (GLOBALVIEW). By contrast, close to the ground, the maximum CO 2 mole fraction is observed late December, early January. The specific seasonal behavior is attributed to the climatology of vertical mixing of the atmosphere in the Carpathian Basin. Nally, 2005; Wunch et al., 2010) . This atmospheric layer can Published by Copernicus Publications on behalf of the European Geosciences Union. Atmos. Chem. Phys., 12, 8865-8875, 2012
doi:10.5194/acpd-12-11539-2012 fatcat:e5plnvvtw5f7fl26hk7fnz6key