Titel corps 28 News Gothic

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Towers at Reserva Biologica do Jaru
Abracos
New tower
2
Seasonal and interannual variation in C flux,
annual net uptake
3
Jaru uptake 5-6 T ha-1 y-1 (1999-2000), . but
recent years seem to show lower uptake (3.4), and
reanalysis using other averaging technique shows
only 1.4 (?) ---gt calculation techniques are
(still) also important issue, especially where
landscape is non-ideal and towers tall. - no
biometry data, no leakage data - no indication
of CO2 losses during calm nights, but confusion
with temperature? (low T correlated with high
windspeeds)
4
The effecct of Friagem on CO2 fluxes in Jaru
(P.J. Oliveira)
Are friagem effects caused by low temperature or
are they simply more windy days?
5
Maybe we should realise that Eddy
correlation DOES NOT measure ecosystem physiology
directly we should fit both physiology and
MICROMETEOROLOGY to the data!
6
Consider the area beneath the sensor a leaky,
sloshing vessel
Fcf(C,u,lm,R,Ps)
U lm
Cf(sum(Fc),Adv)
Advf(C)
Adv
R, Psalpha.PAR
Solve differential equation, fit against data .
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Carbon dioxide fluxes across the Amazon basin
overview of 1999 and 2000 results for EU-
LBA-flux tower sites
Kabat, P.1), Nobre, A D2), Grace, J3) , Manzi,
A4) ,Kruijt, B1), Von Randow, C 4), Elbers, J
E1), Malhi, Y 3), Carswell, F 3), Da Costa, L.5),
Culf, A6), Nobre, C 4), Da Rocha, H 7),
Waterloo, M1), De Araujo, A C2), De Oliveira, P
J4)9), Stefani, P8), Freitas, H7) 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
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EUSTACH Sites
Manaus K34 and Manaus C14
Caxiuana
Rebio Jaru Fazenda Nossa Senhora
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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
CO2 and H2O (CIRAS SC analyser) ) (Not always
present) Meteorological data Automatic weather
station, shortlong wave radiation, etcetera.
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Measured CO2 eddy fluxes over 3 years in the
Central, E. and SW Amazon
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Night-time NEE (Storage corrected) fluxes plotted
against u
Do we have a problem?
? Uncertainty about 7 t ha-1 y-1 ?
?
There is no problem here
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Similarity relations - representativity for
surface
For all sites the basic s(w)/u relations are
good on average
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Energy balance closure at Reserva Jaru and
Fazenda Nossa Senhora
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Seasonal and interannual variation in C flux
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Mean Diurnal trend of CO2 fluxes at four sites

• Dry seasons
• Forest peak uptake similar, nights different.
• Pasture lower uptake!

Dry
Wet

• Wet seasons
• Forests and pasture very similar.

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South African savanna - Hanan et al - AGU talk
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Night time fluxes (respiration?)
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Where is seasonality in Jaru?
Mean Diurnal
Cumulative mean diurnal
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Where is seasonality in Manaus K34?
Mean Diurnal
Cumulative mean diurnal
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Cumulative flux over the day afternoon
slow-down.
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Mean hourly canopy light response curves for four
sites
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Hysteresis in light response seasonally driven?
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(hysteresis in) surface conductance?
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Tentative conclusion Seasonality results from
vriation light regime and (soil) respiration