Overview of gas exchange measurementsfrom leaf level to landscape scalein a semi-arid ecosystem (Mali)

Valérie Le Dantec1, Claire Damesin2, Daniel Epron3, Josiane Seghieri1, Jon Bennie4, Lina Mercado4, Claire Delon5, Richard Dupont5, Dominique Serça5, Colin Lloyd4, Laurent Kergoat1, Eric Mougin1

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 (CO2, H2O, NO)from leaf to canopy scale.

UP S

CA

LING

canopy scale

Local scale

Mesoscale

Leaf scale Soil fluxes

Member press delta T device :Leaf water potential

Li-Cor 6400 :Leaf photosynthesisLeal stomatal conductance

PorometerAP4 :Stomatalconductance

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229 230 231 232 233 234 235 236 237 238 239 240

DoY 2004

SR (

µmo

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-1)

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SW

C (

%)

SR

SW C

17/08/04y = 0,92x + 1,24

R2 = 0,76

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0 1 2 3 4 5 6Root Biomass (g)

Soi

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PAR (µmol m-2 s-1)

FN

C (

µm

ol

m-2

s-1

)

Cenchrus b.

Zornia g.