A recent build-up of atmospheric CO2 over Europe. Part 1: observed signals and possible explanations

Autor: Frédéric Chevallier, Martina Schmidt, Philippe Ciais, C. Aulagnier, Thomas J. Conway, Frank Meinhardt, V. Kazan, Tuula Aalto, Domenico Cipriano, M. Ramonet, Jaroslaw N. Necki, Peter Simmonds, Jean-Daniel Paris, László Haszpra, Irène Xueref-Remy
Rok vydání: 2010
Předmět:
Zdroj: Tellus B: Chemical and Physical Meteorology. 62:1
ISSN: 1600-0889
0280-6509
DOI: 10.1111/j.1600-0889.2009.00442.x
Popis: We analysed interannual and decadal changes in the atmospheric CO 2 concentration gradient (ΔCO 2 ) between Europe and the Atlantic Ocean over the period 1995–2007. Fourteen measurement stations are used, with Mace-Head being used to define background conditions. The variability of ΔCO 2 reflects fossil fuel emissions and natural sinks activity over Europe, as well as atmospheric transport variability. The mean ΔCO 2 increased by 1–2 ppm at Eastern European stations (∼30% growth), between 1990–1995 and 2000–2005. This built up of CO 2 over the continent is predominantly a winter signal. If the observed increase of ΔCO 2 is explained by changes in ecosystem fluxes, a loss of about 0.46 Pg C per year would be required during 2000–2005. Even if severe droughts have impacted Western Europe in 2003 and 2005, a sustained CO 2 loss of that magnitude is unlikely to be true. We sought alternative explanations for the observed CO 2 build-up into transport changes and into regional redistribution of fossil fuel CO 2 emissions. Boundary layer heights becoming shallower can only explain 32% of the variance of the signal. Regional changes of emissions may explain up to 27% of the build-up. More insights are given in the Aulagnier et al. companion paper. DOI: 10.1111/j.1600-0889.2009.00442.x
Databáze: OpenAIRE
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