Carbon, water and energy fluxes in an African savanna ecosystem · 2014. 3. 31. · Map of Kruger...
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Kruger Park Eddy Covariance Study Carbon, water and energy fluxes in an African savanna ecosystem Niall Hanan, Bob Scholes, Jeff Privette AGU Fall Meeting, San Francisco, December 13, 2001
Transcript of Carbon, water and energy fluxes in an African savanna ecosystem · 2014. 3. 31. · Map of Kruger...
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Kruger Park Eddy Covariance Study
Carbon, water and energy fluxes in an African savanna ecosystem
Niall Hanan, Bob Scholes, Jeff Privette
AGU Fall Meeting, San Francisco, December 13, 2001
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Kruger Park Eddy Covariance Study
North from tower: Combretum savanna
South-east from tower: Acacia savanna
Map of Kruger National Park
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Kruger Park Eddy Covariance Study
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Kruger Park Eddy Covariance Study
Fluxes during transition from rainy season - dry season (2000)CO2 Flux
-15
-10
-5
0
5
10
0 6 12 18 24
Hour (local)
CO
2 (µ
mol
m-2
s-1
)
Sensible Heat Flux
-100
0
100
200
300
400
0 6 12 18 24
Hour (local)
H (W
m-2
)
Latent Heat Flux
-100
0
100
200
300
400
0 6 12 18 24
Hour (local)
LE (W
m-2
)
13-Apr13-May30-Jun
u * >0.25 m s -1
Daytime Bowen Ratio
0
1
2
3
4
5
6 9 12 15 18
Hour (local)
H /
LE13-Apr13-May30-Jun
ABS(H,LE) >20 W m -2
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Kruger Park Eddy Covariance Study
Fluxes during 2000-2001 rainy seasonCO2 Flux
-25
-20
-15
-10
-5
0
5
10
0 6 12 18 24
Hour (local)
CO
2 (µ
mol
m-2
s-1
)
Latent Heat Flux
-100
0
100
200
300
400
0 6 12 18 24
Hour (local)
LE (W
m-2
) 09-Dec27-Feb06-May01-Jul
Sensible Heat Flux
-100
0
100
200
300
0 6 12 18 24
Hour (local)
H (W
m-2
)
Daytime Bowen Ratio
0
1
2
3
4
5
6 9 12 15 18
Hour (local)
H /
LE09-Dec27-Feb06-May01-Jul
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Kruger Park Eddy Covariance Study
Savanna fire (Sept 26, 2000): energy balanceSurface Albedo
0
0.1
0.2
0.3
0.4
267 269 271 273 275Day & Time
Albe
do
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
ND
VI
SolarPARNIRNDVI
Net Radiation (W m-2)
-200
0
200
400
600
800
1000
268 269 270 271 272 273Day & Time
Rn (
W m
-2)
SolarTIRRnet
Mark Helmlinger, 9/27/00
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Kruger Park Eddy Covariance Study
Sensible Heat Flux
-200
0
200
400
600
800
1000
0 6 12 18 24
Hour (local)
H (W
m-2
) 27-Aug
31-Aug
01-Sep
CO2 Flux
-100
10203040506070
0 6 12 18 24
Hour (local)
CO
2 (µ
mol
m-2
s-1
)
(120) Latent Heat Flux
-200
-150
-100
-50
0
50
100
150
0 6 12 18 24
Hour (local)
LE (W
m-2
) 27-Aug
31-Aug
01-Sep
Savanna fire (Aug 31, 2001): fluxes
(2500)
(-315)
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Kruger Park Eddy Covariance Study
Contrasting Savanna Types (Acacia and Combretum)May 2000 - Acacia
-25-20-15-10-505
1015
0 100 200 300 400
Incident PAR (W/m2)
CO
2 Fl
ux (u
mol
/m2/
s)
Metrics - Calculated for each month:
Light Response Ecosystem Respiration Amax(slope) (intercept) (asymptote)All three metrics respond to a combination of ecosystem structure (phenology), physiology and environmental variables...
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Kruger Park Eddy Covariance Study
Contrasting Acacia & Combretum Savanna I: SeasonalityKruger Amax by Species
-20
-16
-12
-8
-4
0
Mar-00 Jun-00 Sep-00 Dec-00 Mar-01 Jun-01 Sep-01 Dec-01
Date
Amax
(um
ol/m
2/s)
AcaciaCombretum
Kruger Light Response by Species
-0.12-0.1
-0.08-0.06-0.04-0.02
00.02
Mar-00 Jun-00 Sep-00 Dec-00 Mar-01 Jun-01 Sep-01 Dec-01
Date
Ligh
t res
pons
e (u
mol
/J)
AcaciaCombretum
Kruger Respiration by Species
0
1
2
3
4
5
6
7
Mar-00 Jun-00 Sep-00 Dec-00 Mar-01 Jun-01 Sep-01 Dec-01
Date
Res
pira
tion
(um
ol/m
2/s)
AcaciaCombretum
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Kruger Park Eddy Covariance Study
Contrasting Acacia & Combretum Savanna II: soil moistureKruger Light Response by Species
-0.12
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.025 0.075 0.125 0.175
Soil Water (volumetric)
Ligh
t res
pons
e (u
mol
/J)
AcaciaCombretum
Kruger Amax by Species
-20
-16
-12
-8
-4
0
0.025 0.075 0.125 0.175
Soil water (volumetric)
Amax
(um
ol/m
2/s)
AcaciaCombretum
Kruger Respiration by Species
0
1
2
3
4
5
6
7
0.025 0.075 0.125 0.175
Soil water (volumetric)
Res
pira
tion
(um
ol/m
2/s)
AcaciaCombretum
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Kruger Park Eddy Covariance Study
Contrasting Acacia & Combretum III: soil water potentialKruger Light Response by Species
-0.14-0.12
-0.1-0.08-0.06-0.04-0.02
00.02
0 1 10 100
Soil Water Potential (-MPa)
Ligh
t res
pons
e (u
mol
/J)
AcaciaCombretum
Kruger Amax by Species
-20
-16
-12
-8
-4
0
0.1 1 10 100
Soil Water Potential (-MPa)
Amax
(um
ol/m
2/s)
AcaciaCombretum
Kruger Respiration by Species
0
1
2
3
4
5
6
7
0.1 1 10 100
Soil Water Potential (-MPa)
Res
pira
tion
(um
ol/m
2/s)
AcaciaCombretum
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Kruger Park Eddy Covariance Study
Future Research at the Skukuza Tower Site• Continue flux measurements
• Continue (add) companion studies– NPP & canopy structure
– soil and vegetation BGC– EOS validation– leaf-level physiology
– soil CO2– terrestrial trace gas studies (NOx, VOC, CH3)
– (Carbon and oxygen stable isotope studies)
• Model analyses– biophysical modeling – radiative transfer
– BGC and trace gas modeling
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Kruger Park Eddy Covariance Study
Agencies & Acknowledgements
NASA, Terrestrial Ecology ProgramNSF, Biocomplexity in the
Environment Program South African Center for Scientific
and Industrial Research (CSIR)NASA, EOS Validation OfficeScientific Services, Kruger National
ParkSouth African National Research
Foundation
Carbon, water and energy fluxes in an African savanna ecosystemAgencies & Acknowledgements
