Open AccessDetecting the critical periods that underpin interannual fluctuations in the carbon balance of European forests
Author(s) -
le Maire Guerric,
Delpierre Nicolas,
Jung Martin,
Ciais Philippe,
Reichstein Markus,
Viovy Nicolas,
Granier André,
Ibrom Andreas,
Kolari Pasi,
Longdoz Bernard,
Moors Eddy J.,
Pilegaard Kim,
Rambal Serge,
Richardson Andrew D.,
Vesala Timo
Publication year - 2010
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009jg001244
Subject(s) - environmental science , ecosystem , ecosystem respiration , primary production , climate change , climatology , atmospheric sciences , flux (metallurgy) , carbon cycle , forest ecology , precipitation , physical geography , ecology , geography , oceanography , geology , meteorology , biology , materials science , metallurgy
The interannual variability of CO 2 exchange by forest ecosystems in Europe was analyzed at site and regional scales by identifying critical periods that contributed to interannual flux anomalies. Critical periods were defined as periods in which monthly and annual flux anomalies were correlated. The analysis was first conducted at seven European forest flux tower sites with contrasting species and climatic conditions. Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE), a generic process‐based model, represented fairly well most features of the critical period patterns and their climate drivers at the site scale. Simulations at the scale of European forests were performed with ORCHIDEE integrated at a 0.25° spatial resolution. The spatial and temporal distributions of critical periods for canopy photosynthesis, ecosystem respiration, and net ecosystem exchange (NEE) as well as their underlying climate drivers were analyzed. The interannual variability in gross primary productivity (GPP) was explained by critical periods during spring and summer months. In contrast, the interannual variability in total ecosystem respiration (TER) was explained by critical periods occurring throughout the year. A latitudinal contrast between southern and northern Europe was observed in the distributions of critical periods for GPP and TER. The critical periods were positively controlled by temperature in northern Europe and by soil water availability in southern Europe. More importantly, the latitudinal transition between temperature‐driven and water‐driven critical periods for GPP varied from early spring to late summer. Such a distinct seasonal regime of critical periods was less clearly defined for TER and NEE. Overall, the critical periods associated with NEE variations and their meteorological drivers followed those associated with GPP.