European land CO2 sink influenced by NAO and East-Atlantic Pattern coupling

Ana Bastos (1, 2) , Ivan A. Janssens (3) , Célia M. Gouveia (4) , Ricardo M. Trigo (2) , Philippe Ciais (1, 5) , Frédéric Chevallier (1, 6) , Josep Peñuelas (7, 8) , Christian Rödenbeck (9) , Shilong Piao (10) , Pierre Friedlingstein (11) , Steven W. Running (12)

1 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
2 Instituto Dom Luiz
3 Universiteit Antwerpen = University of Antwerpen [Antwerpen]
4 INESC TEC - Institute for Systems and Computer Engineering, Technology and Science [Porto]
5 ICOS-ATC - ICOS-ATC
6 SATINV - Modélisation INVerse pour les mesures atmosphériques et SATellitaires
7 CREAF - Centre for Ecological Research and Applied Forestries
8 UAB - Universitat Autònoma de Barcelona = Autonomous University of Barcelona = Universidad Autónoma de Barcelona
9 Max-Planck-Institut
10 Peking University [Beijing]
11 EMPS - College of Engineering, Mathematics and Physical Sciences [Exeter]
12 Numerical Terradynamics Simulation Group

Large-scale climate patterns control variability in the global carbon sink. In Europe, the North-Atlantic Oscillation (NAO) influences vegetation activity, however the East-Atlantic (EA) pattern is known to modulate NAO strength and location. Using observation-driven and modelled data sets, we show that multi-annual variability patterns of European Net Biome Productivity (NBP) are linked to anomalies in heat and water transport controlled by the NAO-EA interplay. Enhanced NBP occurs when NAO and EA are both in negative phase, associated with cool summers with wet soils which enhance photosynthesis. During anti-phase periods, NBP is reduced through distinct impacts of climate anomalies in photosynthesis and respiration. The predominance of anti-phase years in the early 2000s may explain the European-wide reduction of carbon uptake during this period, reported in previous studies. Results show that improving the capability of simulating atmospheric circulation patterns may better constrain regional carbon sink variability in coupled carbon-climate models.

Domaines: Océan, Atmosphère; Climatologie

Ana Bastos, Ivan A. Janssens, Célia M. Gouveia, Ricardo M. Trigo, Philippe Ciais, et al.. European land CO2 sink influenced by NAO and East-Atlantic Pattern coupling. Nature Communications, 2016, 7, pp.10315. ⟨10.1038/ncomms10315⟩. ⟨hal-01585006⟩