1. Overview of gas exchange measurements from leaf level to landscape scale in a semi-arid ecosystem (Mali) Valérie Le Dantec 1, Claire Damesin 2, Daniel Epron 3, Josiane Seghieri 1, Jon Bennie 4, Lina Mercado 4, Claire Delon 5, Richard Dupont 5, Dominique Serça 5, Colin Lloyd 4, Laurent Kergoat 1, Eric Mougin 1 1 Centre d'Etudes Spatiales de la Biosphère, Toulouse (France) & Bamako (Mali) 2 Ecologie Systématique et Evolution, Université Paris XI, Orsay (France) 3 Ecologie et Ecophysiologie forestières, Université Nancy 1, Nancy (France) 4 Centre for Ecology and Hydrology, Wallingford (U.K.) 5 Laboratoire d'aérologie, Toulouse (France) The objectives were : - to improve understanding and modelling of plant and soil processes to understand land surface-atmosphere - to collect data to parameterise and to validate SVAT models at the local scale. When? Intensives field campaigns - During the EOP of AMMA. - During maximal plant growing period (July-August) Where? In a semi-arid ecosystem (super site Agoufou, Mali) coordinating, co-localising instruments & experimentations How? intensive gas exchange measurements (CO 2, H 2 O, NO) from leaf to canopy scale.

2. UP SCALING canopy scale Local scale Mesoscale Porometer AP4 : Stomatal conductance Leaf scaleSoil fluxes