RT info:eu-repo/semantics/article T1 Features of the annual evolution of CO2 and CH4 in the atmosphere of a Mediterranean climate site studied using a nonparametric and a harmonic function A1 Pérez Bartolomé, Isidro Alberto A1 Sánchez Gómez, María Luisa A1 García Pérez, María Ángeles A1 Pardo Gómez, Nuria AB Concentrations of CO2 and CH4 measured over 3 years at a rural site in the Spanish northern plateau were investigated together with vegetation and meteorological variables. Two procedures were implemented to study the annual evolution. Kernel estimation provided a detailed time description, and the harmonic model may be fitted easily. The site was characterised by grass from autumn to spring. However, vigorous growth was observed during the latter season due to the biological cycle of plants under favourable meteorological conditions. A CO2 peak was observed a fortnight before the time of maximum NDVI, andwas attributed to the prevalence of respiration over photosynthesis. A pronounced trough was apparent in summer and was explained by the death of vegetation and active dispersion in a highly developed boundary layer. CH4 evolution was characterised by a deficit period from May to October, indicating that meteorological evolution played a key role. The harmonic model showed that annual and half-annual cycles evidenced a similar contribution for CO2, whereas said weight for the half-annual cycle was considerably smaller for CH4. PB ELSEVIER YR 2016 FD 2016 LK http://uvadoc.uva.es/handle/10324/32891 UL http://uvadoc.uva.es/handle/10324/32891 LA eng NO Atmospheric Pollution Research 7 2016 1013-1021 DS UVaDOC RD 28-mar-2024