Carbon dioxide fluxes across the Amazon basin: overview of 1999 and 2000 results for EU- LBA-flux tower sites Kabat, P. 1), Nobre, A D 2), Grace, J 3), Manzi, A 4),Kruijt, B 1), Von Randow, C 4), Elbers, J E 1), Malhi, Y 3), Carswell, F 3), Da Costa, L. 5), Culf, A 6), Nobre, C 4), Da Rocha, H 7), Waterloo, M 1), De Araujo, A C 2), De Oliveira, P J 4)9), Stefani, P 8), Freitas, H 7) 1) Alterra, NL, 2) INPA, Brazil, 3) Edinburgh University, UK, 4) CPTEC/INPE, Brazil, 5) UFPA,MPEG, EMBRAPA, Brazil, 6) CEH, UK, 7)USP, Brazil, 8) Universita della Tuscia, Italy, 9) ULBRA, UNIR, Brazil

EUSTACH Sites Manaus K34 and Manaus C14 Caxiuana Rebio Jaru Fazenda Nossa Senhora

Towers at Reserva Biologica do Jaru ‘Abracos’ New tower

Methods Eddy correlation: Systems based on ‘Edisol’ (Moncrieff et al, 1996) and ‘Euroflux’ (Aubinet et al, 1999) closed-path principle. Gill-Solent 3-D sonic anemometer Li-Cor 6262 Gas analyser SHORT tube, high pumping rate Calculation: delay removal, 3 rotations, 800s recursive detrend, correction for detrend loss of low frequencies (Except at Caxiuana) Storage fluxes: (in-canopy profiles of CO 2 and H 2 O (CIRAS SC analyser) ) (Not always present) Meteorological data: Automatic weather station, short&long wave radiation, etcetera.

Measured CO 2 eddy fluxes over 2 years in the Central and Southern Amazon Data are 10-day averages. Missing data are green or dark blue

? Night-time NEE (Storage corrected) fluxes plotted against u* Do we have a problem? There is no problem here ? Uncertainty about 7 t ha -1 y -1 ?

5-6 T ha -1 y T ha -1 y -1 Seasonal and interannual variation in C flux, annual net uptake

Mean Diurnal trend of CO 2 fluxes at four sites Dry Wet Dry seasons: Forest peak uptake similar, nights different. Pasture lower uptake! Wet seasons: Forests and pasture very similar.

Where is seasonality in Jaru? Mean Diurnal Cumulative mean diurnal

Where is seasonality in Manaus K34? Mean Diurnal Cumulative mean diurnal

Mean hourly canopy light response curves for four sites

Ecosystem response at monthly time scales Radiation Rainfall

Similarity relations - representativity for surface For all sites the basic s(w)/u* relations are good on average

The effecct of Friagem on CO 2 fluxes in Jaru (P.J. Oliveira) Are friagem effects caused by low temperature or are they simply more windy days?

Energy balance closure at Reserva Jaru and Fazenda Nossa Senhora