1. Introduction 2. Measurements of sun-induced fluorescence (SIF ...
Transcript of 1. Introduction 2. Measurements of sun-induced fluorescence (SIF ...
RELATIONSHIP BETWEEN SUNAND GROSS PRIMARY PRODUCTION IN A WHEAT CROP
Goulas Y.*, Fournier A.*, Daumard F.*,
*Laboratoire de Météorologie Dynamique, Centre National de la Recherche Scientifique, Ecole Polytechnique, 91128 Palaiseau Cedex, FrancePolytechnique, 91128 Palaiseau Cedex, France
+ Institut National de la Recherche Agronomique (INRA), Avignon, France
1. Introduction1. IntroductionChlorophyll fluorescence (ChlF) is a light emission produced by photosynthetic pigments from their excitedcompetes with other deactivation pathways such as pototochemistry and heat dissipation. At leaf level,Development of new techniques based on the filling-in of absorption bands in the solar spectrum enablespossibilities of remote sensing of vegetation fluorescence (Plascyk 1975, Moya et al. 2004, for aempirically show a strong linear correlation between sun-induced fluorescence (SIF) and gross primaryHowever, the rationale of the observed correlation still remains unclear. Here, we investigated theHowever, the rationale of the observed correlation still remains unclear. Here, we investigated theseasonal cycle and analyzed how it is affected by experimental conditions and environmental parameters
SIF has been measured in the oxygen absorption bands at two wavelengths (red , F687; far red, F760) at the Avignon experimental site with
2. Measurements of sun-induced fluorescence (SIF) and gross2. Measurements of sun-induced fluorescence (SIF) and gross
Eddy tower
Eddy footprint
SIF target
SIF fov
The SIF instrument Triflex mounted on acrane at the Avignon experimental site.(Daumard et al., 2010, 2012
3. Correlations between SIF and GPP3. Correlations between SIF and GPP
experimental site with the TriFlex instrument build in LMD (Daumardet al. 2010).
A strong correlation is found between GPP and F760
The correlation is much weaker between GPP and F687
Meteo station
SIF fov
Aerial view of the Avignon experimental site atINRA (Institut National de la RechercheAgronomique).
50
40
30
GPP
(µm
oles
C m
-2 s
-1 )
r 2
=0.8350
40
30
GPP
(µm
oles
C m
-2 s
-1 ) r
2=0.34
4. Analysis of the SIF-GPP relationship4. Analysis of the SIF-GPP relationship
GPP APAR LUE ThefactorsWe
GPP and F760 when data are integrated over the day (r2=0.83).
and F687 (r2=0.34).
The relationship between GPP and SIF was analyzedwith simple models following Monteith’s approach ofcanopy productivity (Monteith 1972). As fluorescence
30
20
10
0
GPP
(µm
oles
C m
2.0x101.51.00.50.0
F760 (W m-2 sr-1 nm-1)
30
20
10
0
GPP
(µm
oles
C m
6004002000
F687 (W m-2 sr-1 nm-1)
F F
GPP APAR LUESIF APAR
WeAPAReddyfluorescencethe
Fluorescence yield:Results show that variation range of Fis limited (25-35%) compared to LUE(280%). F shows a biphasic variationpattern with PAR: it increases with PAR
canopy productivity (Monteith 1972). As fluorescenceemission and photosynthesis both occur from energyabsorbed by photosynthetic pigments, GPP and SIFshare a common factor: the AbsorbedPhotosynthetically Active Radiation (APAR).
High Low
25x10-6
20
15
F760
/PA
R (n
m-1
)
0.45
0.40
0.35
0.30
0.25
F
Relationship betweennormalization: Underrelationship is almostand low light levels
Reabsorption factor:The role of F in SIF can be assessed bymonitoring the fluorescence emissionratio (F760/F687) during periods whenchlorophyll content remains stable.
pattern with PAR: it increases with PARat low to moderate irradiation levels anddecreases over 1000 moles m-2 s-1. Fpoorly correlates with LUE (r2=0.11),which induces a decorrelation in the SIF-GPP relationship.
10
5
0
F760
/PA
R (n
m-1
)
0
GPP/PAR (moles C/moles quanta)
3.5
3.0
2.5
2.0
F760
/F68
7
0.20150010005000
PAR (moles/m2/s)
0.4
0.3
0.2
0.1
0.0
F
40x10-33020100LUE (moles C/ moles photons)
r2=0.11
5. Conclusions5. Conclusions A strong correlation is found between daily GPP and far red fluorescence (F760). Variations of APAR induced by canopy develop
GPP and red fluorescence (F687) are poorly correlated.
LUE variations are not reflected by proportional fluorescence yield variations.
Red emission at 687 nm is strongly impacted by reabsorption of fluorescence through canopy, depending on geometry.
and low light levelsregression line (redin a loss of correlation
chlorophyll content remains stable.Results show that F strongly depends oncanopy development and on illuminationgeometry (Fournier et al. 2012).
2.0
1.5
1.0
0.5
F760
/F68
7
0.50.40.30.20.1
Vegetation height (m)
This work has been undertakenwith the support from : PNTS
Red emission at 687 nm is strongly impacted by reabsorption of fluorescence through canopy, depending on geometry.
Fluorescence must be corrected for APAR and F variations to be interpreted in terms of physiological state (
6. References6. ReferencesDaumard, F., et al., IEEE Transactions in Geoscience and Remote Sensing, 2010. 48(9): p. 3358-3368.Daumard, F., et al., IEEE Transactions on Geoscience and Remote Sensing, 2012. 50(11): p. 4292-4300.Fournier, A., et al, ISPRS Journal of Photogrammetry and Remote Sensing, 2012. 68(0): p. 112-120.Frankenberg, C., et al., Geophys. Res. Lett., 2011. 38(17): p. L17706.
Joiner, J., et al., Biogeosciences, 2011. 8(3): p. 637Kowalski, S., et al., Global Change Biology, 2003. Meroni, M., et al., Remote Sensing of Environment, 2009. Monteith, J.L., Journal of Applied Ecology, 1972.
RELATIONSHIP BETWEEN SUN-INDUCED FLUORESCENCE AND GROSS PRIMARY PRODUCTION IN A WHEAT CROP
Goulas Y.*, Fournier A.*, Daumard F.*, Ounis A.*, Marloie O.+, Moya I.*
*Laboratoire de Météorologie Dynamique, Centre National de la Recherche Scientifique, Ecole Polytechnique, 91128 Palaiseau Cedex, FrancePolytechnique, 91128 Palaiseau Cedex, France
Institut National de la Recherche Agronomique (INRA), Avignon, France
excited state. It is regarded as a promising tool for remote sensing of photosynthetic activity since itlevel, ChlF is widely used to evaluate photosynthetic activity at the laboratory or in the field.enables to quantify the fluorescence emission excited by natural light and considerably extends thereview see Meroni et al 2009). Global maps of vegetation fluorescence have been produced that
primary production (GPP) (Joiner et al. 2011, Frankenberg et al. 2011).the SIF-GPP relationship on a wheat crop (Triticum turgidum durum, cultivar Daker) over a completethe SIF-GPP relationship on a wheat crop (Triticum turgidum durum, cultivar Daker) over a complete
parameters (PAR, growth stage, emission wavelength, integration time).
gross primary production (GPP) on a wheat cropgross primary production (GPP) on a wheat crop
50403020100m
oles C
m-2
s-1
2.0
1.5-1 nm
-1
0.80.60.40.20.0mW
m-2
sr-1
nm-1
2000
1500
1000
500
0
mole
s m-2
s-1
F687
F760
GPP
PARCO2 fluxes were measured continuously using the eddy covariance technique at 30 mn intervals. Net CO2 fluxes were partitioned into GPP and
1601401201008060day of the year
1.5
1.0
0.5
0.0mW m
-2sr-1
nm F760
When considering 30 mnintervals data, the correlation is weaker for the GPP-F760 relationship
partitioned into GPP and ecosystem respiration following the method described in Kowalski et al. 2003. Time course of canopy variables and remote sensing signals over a seasonal cycle from March
1st to June 19th 2010.
50
40
30
GPP
(µm
oles
C m
-2 s
-1 ) r
2=0.63 50
40
30
GPP
(µm
oles
C m
-2 s
-1 ) r
2=0.31
The level of correlation between GPP and SIF is dependent on the relationships between the otherfactors: LUE (Light Use Efficiency), F (fluorescence yield at leaf level) and F (reabsorption factor).We investigated these factors by means of independent measurements at leaf and canopy level.
the GPP-F760 relationship (r2=0.63), while it is unchanged for red fluorescence (r2=0.31).
30
20
10
0G
PP (µ
mol
es C
m2.0x101.51.00.50.0
F760 (W m-2 sr-1 nm-1)
30
20
10
0
GPP
(µm
oles
C m
800x106004002000
F687 (W m-2 sr-1 nm-1)800x10
Relationship between GPP and SIF for 30mn intervals data.
We investigated these factors by means of independent measurements at leaf and canopy level.APAR was estimated from light transmitted through canopy. LUE was derived from GPP obtained byeddy covariance. A relative value of fluorescence yield F was obtained by measuring stationaryfluorescence under constant excitation with a PAM-2000 fluorometer on randomly selected leaves inthe canopy.
growthmaturity
senescence0.8
coef
ficie
nt r
2
LAI maximizedCorrelation of GPP with PAR, F760 and F687 are within the same range
LAI increaseHighest correlation of GPP with F760 and LAI
High irradianceLow LUE
Low irradianceHighLUE
between SIF and GPP after PARUnder moderate incident light, the
almost linear (green points). Highlevels induce a deviation from the
senescence0.8
0.6
0.4
0.2
0.0
r2
60-130 70-140 80-150 100-160Time period
GPP-F760
GPP-PAR
GPP-F687
GPP-LAI
Pear
son’
sco
rrel
atio
nco
effic
ient
r
Regression time period
Decrease in ChlCorrelation with F760 increases(no LAI measurement)
Correlation coefficient of the linear regression betweenGPP and canopy variables (F760, F687, PAR, LAI) as afunction of the time period considered for regressionanalysis. Highest correlation is obtained for F760 during
60x10-35040302010
GPP/PAR (moles C/moles quanta)
140012001000800
Mean daily irradiance (moles m-2 s-1)
A strong correlation is found between daily GPP and far red fluorescence (F760). Variations of APAR induced by canopy development are the main source of correlation.
of fluorescence through canopy, depending on geometry.
levels induce a deviation from the(red and blue points), which results
correlation in the SIF-GPP relationship.
analysis. Highest correlation is obtained for F760 duringgrowth. When crop is in a steady state, GPP correlatesat the same level with F760, F687 and PAR.
of fluorescence through canopy, depending on geometry.
variations to be interpreted in terms of physiological state (F).
8(3): p. 637-651.Global Change Biology, 2003. 9(7): p. 1051-1065.Remote Sensing of Environment, 2009. 113(10): p. 2037-2051.
Journal of Applied Ecology, 1972. 9(3): p. 747-766.
Moya, I., et al., Remote Sensing of Environment, 2004. 91(2): p. 186-197.Plascyk, J.A., Optical Eng., 1975. 14(4): p. 339-346.