On the ability of a global atmospheric inversion to constrain variations of CO2 fluxes over Amazonia

The exchanges of carbon, water and energy be- tween the atmosphere and the Amazon basin have global im- plications for the current and future climate. Here, the global atmospheric inversion system of the Monitoring of Atmo- spheric Composition and Climate (MACC) service is used to study the seasonal and interannual variations of biogenic CO 2 fluxes in Amazonia during the period 2002-2010. The system assimilated surface measurements of atmospheric CO 2 mole fractions made at more than 100 sites over the globe into an atmospheric transport model. The present study adds measurements from four surface stations located in tropical South America, a region poorly covered by CO 2 ob- servations. The estimates of net ecosystem exchange (NEE) optimized by the inversion are compared to an independent estimate of NEE upscaled from eddy-covariance flux mea- surements in Amazonia. They are also qualitatively evaluated against reports on the seasonal and interannual variations of the land sink in South America from the scientific literature. We attempt at assessing the impact on NEE of the strong droughts in 2005 and 2010 (due to severe and longer-than- usual dry seasons) and the extreme rainfall conditions regis- tered in 2009. The spatial variations of the seasonal and in- terannual variability of optimized NEE are also investigated. While the inversion supports the assumption of strong spatial heterogeneity of these variations, the results reveal critical limitations of the coarse-resolution transport model, the sur- face observation network in South America during the recent years and the present knowledge of modelling uncertainties in South America that prevent our inversion from capturing the seasonal patterns of fluxes across Amazonia. However, some patterns from the inversion seem consistent with the anomaly of moisture conditions in 2009.

Détails bibliographiques

Auteurs principaux:	95032 Molina, Luis CEA-CNRS-UVSQ, IPSL, Gif-sur-Yvette, France, 51355 Broquet, Gregoire CEA-CNRS-UVSQ, IPSL, Gif-sur-Yvette, France (autor/a), 79675 Imbach Bartol, Pablo Andrés CATIE, Turrialba, Costa Rica (autor/a), 57090 Chevallier, Frederic CEA-CNRS-UVSQ, IPSL, Gif-sur-Yvette, France (autor/a), 106574 Poulter, Benjamin Montana State University, Bozeman, USA (autor/a), 49840 Bonal, Damien INRA, UMR EEF, Champenoux, France (autor/a), 51909 Burban, B. INRA, UMR Ecofog, Avenue de France (autor/a), 108648 Ramonet, Michel CEA-CNRS-UVSQ, IPSL, Gif-sur-Yvette, France (autor/a), 71099 Gatti, Luciana Vanni CNEN - IPEN - Lab. Quimica Atmosferica, Cidade Universitaria, São Paulo, Brazil (autor/a), 131938 Wofsy, Steven C. Harvard University, Cambridge, USA (autor/a) ...[y otros 3]
Format:	Texto biblioteca
Langue:	eng
Sujets:	DIOXIDO DE CARBONO, IMPACTO AMBIENTAL, CO2 ATMOSFERICO, INVERSION TERMICA, ATMOSFERA, VIGILANCIA, OBSERVACIONES METEOROLOGICAS, CONDICIONES ATMOSFERICAS, CUENCAS HIDROGRAFICAS, AMAZONIA, CAMBIO CLIMÁTICO,
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