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#9#118
#11#13#14
SOC Camera Images & Tree Samples
SOC camera image @ 09/05 11:01 am, composited by R-G-BTag # Family
9 Vochysiaceae
11 Leguminosae-Caesalpinioideae
13 Sapotaceae
14 Lecythidaceae
118 Leguminosae-Caesalpinioideae
TR9 TR11 TR13 TR14 TR118Legend Shade Region: 95% confidence interval
The reflectance signal in this panel was derived from SOC camera @ 09/05
11:01 am
The ASD spectral in this panel: (1) was collected within one week comparable with SOC image (09/05);
(2) represented the primary leaf age spectral signal
Spectral Comparisons between ASD & SOC camera
Leaf level spectral
Sunlit leaves
The central line is the mean value of 3*3 pixels
Sun branch
TR9 TR11 TR13 TR14 TR118Legend Shade Region: 95% confidence interval
The reflectance signal in these two panels were derived from SOC camera @ 09/05 11:01 am
Spectral Comparisons of SOC camera images between leaf level and canopy level
Leaf level spectral
Sunlit leaves
The central line is the mean value of 3*3 pixels
Canopy level spectral
Both Sunlit leaves and shade leaves
The central line is the mean value of ~20*20 pixelsIncrease the uncertainty of the spectral
Seasonal Change in NDVI (leaf level)
(1): the selection of the camera images—i) first camera angle, within the time window 10:00 am -12:00pm; ii) starting from 07/23/2012 until 10/07/2012, with 5-day interval
(2)The NDVI calculation—i) average signal for the sunlit leaves of each focal tree (3*3 pixels); ii) NDVI=(NIR-red)/(NIR+red),
where NIR used the MODIS band 2 (841-876nm), while red used the MODIS band 1
(620-620 nm)
Average NDVI of images each day NDVI of each image Outlier of NDVI
Seasonal Change in NDVI (sub-canopy level)
(1): the selection of the camera images—i) first camera angle, within the time window 10:00 am -12:00pm; ii) starting from 07/23/2012 until 10/07/2012, with 5-day interval
(2)The NDVI calculation—i) average signal for the sunlit leaves of each focal tree (20*20
pixels); ii) NDVI=(NIR-red)/(NIR+red), where NIR used the MODIS band 2 (841-
876nm), while red used the MODIS band 1 (620-670 nm)
Average NDVI of images each day NDVI of each image Outlier of NDVI
283.28266.04
263.80204.08
328.14
110.266
78.15 218.39
362.4
283.5
326.56
120.8 247.46
Seasonal Change in NDVI (leaf level) & leaf traits (1-m branch accumulated dry leaf mass)
NDVI Average NDVI of each image Outlier of NDVITiming of ground 1-m sun branch sample
The accumulated 1-m branch dry leaf mass
111:12:277
100:101:206
Seasonal Change in NDVI (leaf level) & leaf demography traits (1-m branch accumulated dry leaf mass)
NDVI Average NDVI of each image Outlier of NDVITiming of ground 1-m sun branch sample
Leaf demography(the leaf number of each age class)
144:11:239
Y:M:O116:223:53 387:632:309
Y:M:O
304:832:4599:72
M:O
82
M
0:0:166
Y:M:O
117
314 2:236:9728:16:177
6 Focal Trees & ASD Spectral Reflectance of leaf ages
Y1 Y2 Y3/Y M O
0.65
0.7
0.75
0.8
0.85
0.9
1 2 3 4 5
Leaf Age Classes
ND
VI
TR#118
6 Focal Trees NDVI & Leaf Demography
0.7
0.75
0.8
0.85
1 2 3 4 5
Leaf Age Classes
ND
VI
TR#9
0.6
0.65
0.7
0.75
0.8
0.85
1 2 3 4 5
Leaf Age Classes
ND
VI
TR#11
0.87
0.88
0.89
0.9
1
Leaf Age Classes
ND
VI
TR#14
0.84
0.86
0.88
0.9
1 2
Leaf Age Classes
ND
VI
TR#500
0.78
0.8
0.82
0.84
0.86
0.88
0.9
1 2 3
Leaf Age Classes
ND
VI
TR#504
Y1 Y2 Y3 M O Y1 Y2 Y3 M O
Y1 Y2 Y3 M O M
O
Y M O
M
NDVI= Where red: modis band 1 (620nm-670nm); NIR: modis band 2 (841nm-876 nm); blue: modis band 3 (459 nm – 479 nm)
0.5
0.52
0.54
0.56
0.58
0.6
0.62
1 2 3
Leaf Age Classes
EV
I
TR#504
0.6
0.65
0.7
0.75
1 2
Leaf Age Classes
EV
I
TR#500
0.45
0.5
0.55
0.6
0.65
0.7
1 2 3 4 5
Leaf Age Classes
EV
I
TR#118
0.35
0.4
0.45
0.5
0.55
1 2 3 4 5
Leaf Age Classes
EV
I
TR#11
0.4
0.45
0.5
0.55
0.6
1 2 3 4 5
Leaf Age Classes
EV
I
TR#9
6 Focal Trees EVI & Leaf Demography
Y1 Y2 Y3 M O
Y1 Y2 Y3 M O
Y1 Y2 Y3 M O M
O
Y M O
0.56
0.58
0.6
0.62
1
Leaf Age Classes
EV
I
TR#14
M
Where red: modis band 1 (620nm-670nm); NIR: modis band 2 (841nm-876 nm); blue: modis band 3 (459 nm – 479 nm)
Part 2: RS Based Trait Estimation Approach 1: Vegetation Index
Figure 3 from Hilker et al. 2010. Remote Sensing of Environment
Two forest types in Canada
PRI (Photosynthetic Reflectance Index)
400 500 600 700 800 900 10000
10
20
30
40
50
60
Rel
fect
ance
%
Wavelength(nm)
PRI=
Light use efficiency generated by eddy
covariance measurement
Xanthophyll induced absorption feature at 531 nm, which is intimately linked to the biochemical mechanism down-regulating photosynthesis
-0.06
-0.04
-0.02
0
0.02
0.04
1 2 3
Leaf Age ClassesP
RI
TR#504
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
1 2
Leaf Age Classes
PR
I
TR#500
-0.04
-0.02
0
0.02
1 2 3 4 5
Leaf Age Classes
PR
I
TR#118
0
0.01
0.02
0.03
0.04
0.05
1
Leaf Age Classes
PR
I
TR#14
0
0.02
0.04
0.06
1 2 3 4 5
Leaf Age Classes
PR
I
TR#11
-0.15
-0.1
-0.05
0
0.05
1 2 3 4 5
Leaf Age Classes
PR
I
TR#9
6 Focal Trees PRI & Leaf Demography
Y1 Y2 Y3 M OY1 Y2 Y3 M O
Y1 Y2 Y3 M OM
OY M O
M
PRI (Photosynthetic Reflectance Index)PRI=
Ecosystem Average Vegetation Index (6 Focal Trees)& Leaf Demography
0.6
0.65
0.7
0.75
0.8
0.85
0.9
1 2 3 4 5
Leaf Age Classes
ND
VI
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
1 2 3 4 5
Leaf Age Classes
EV
I
-0.14
-0.12
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
1 2 3 4 5
Leaf Age Classes
PR
I
Y1 Y2 Y3 M O Y1 Y2 Y3 M O Y1 Y2 Y3 M O
6 8 10 12 14 16 180.7
0.8
0.9
1
Time (Hour@09/20/2012)
ND
VI
Angle 1 & Angle 2
6 8 10 12 14 16 180.7
0.8
0.9
1
Time (Hour@09/20/2012)
ND
VI
Angle 2 & Angle 3
6 8 10 12 14 16 180.7
0.8
0.9
1
Time (Hour@09/20/2012)
ND
VI
Angle 3 & Angle 4
6 8 10 12 14 16 180.7
0.8
0.9
1
Time (Hour@09/20/2012)
ND
VI
Angle 4 & Angle 5
Angle 1(~75 o)
Angle 2(~60 o)
Angle 3(~45 o)
Angle 4(~30 o) Angle 5
(~15 o)
Angle 4(~30 o)
Angle 3(~45 o)
Angle 2(~60 o)
O Angle 1 Angle 2
O Angle 2 Angle 3
O Angle 3 Angle 4
O Angle 4 Angle 5
NDVI & Camera Angle Effect
Take Home message:(1) Camera angle doesn’t affect NDVI value if the camera
sensed the same object?(2) Camera angle does affect NDVI if the camera sensed
the different object, due to shade effect?(3) 10 am for MODIS pass-by minimized the shade effect?
