Variation of CO<sub>2</sub> mole fraction in the lower free troposphere, in the boundary layer and at the surface
Eight years of occasional flask air sampling and 3 years of frequent in situ measurements of carbon dioxide (CO<sub>2</sub>) 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 vertic...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2012-09-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/12/8865/2012/acp-12-8865-2012.pdf |
| Summary: | Eight years of occasional flask air sampling and 3 years of frequent in situ measurements of carbon dioxide (CO<sub>2</sub>) 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<sub>2</sub> 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<sub>2</sub> mole fraction during the mid-afternoon fairly well, with an underestimation of 0.27–0.85 μmol mol<sup>−1</sup> in summer, and an overestimation of 0.66–1.83 μmol mol<sup>−1</sup> in winter. The seasonal cycle of CO<sub>2</sub> mole fraction is damped with elevation. While the amplitude of the seasonal cycle is 28.5 μmol mol<sup>−1</sup> at 10 m above the ground, it is only 10.7 μmol mol<sup>−1</sup> 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<sub>2</sub> 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. |
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| ISSN: | 1680-7316 1680-7324 |