Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Soil Moisture Retrieval Under Vegetation Using Dual Polarized PALSAR Data
Christian Koyama & Karl SchneiderDepartment of Geosciences
University of CologneIGARSS 2011 Vancouver
July 26, 2011
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Outline
• Test Site & Field Measurements
• ALOS PALSAR Data & Processing
• Grassland Soil Moisture Retrieval Model
• High Resolution Surface Soil Moisture Patterns
• Conclusions
- 02 -TABLE OF CONTENTS
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Grass layerLayer depth: 5 – 175 cmDielectric constant: 15 – 25 Blade density: 1000 – 3000/m²Grass biomass: 0.2 – 3.1 kg/m²Thatch layer
Layer depth: 2 – 4 cmDielectric constant: 6 – 70Soil half spaceDielectric constant: 9.7 – 33.8Texture: clay/silt loam
GROUND TRUTH DATA(test site and field measurements)
- 03 -
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
PALSAR Fine Mode Dual Polarization DataRegion: Track 647+648 / Frame 1000+1010
Ground Range Resolution: 15 m
Center Frequency: L-band @ 1,270 MHz
Chirp Bandwidth: 14 MHz
Polarization: HH + HV
Off-Nadir Angle: 34.3 deg.
2007 2008 2009
Track 647Track 648
10/2
1/20
09
5/4/
2008
6/2/
2008
6/19
/200
8
7/18
/200
8
6/22
/200
9
7/21
/200
9
9/5/
2009
9/22
/200
9
9/17
/200
7
8/2/
2007
Soil moisture
Surface roughness
Biomass
ALOS PALSAR FBD343 DATA(product description & acquisition overview)
- 04 -
Jan.
Feb. Mar. Apr
.M
ayJu
ne July
Aug.
Sep.
Oct. Nov.
Dec.
Aug.
Sep.
Oct. Nov.
Dec.
Jan.
Feb. Mar. Apr
.M
ayJu
ne July
Aug.
Sep.
Oct. Nov.
Dec.
Jan.
Feb. Mar. Apr
.M
ayJu
ne
5/10
/201
0
6/25
/201
0
2010
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
ALOS PALSAR FBD343 Level 1.1
Multi-looking
Coregistration + Generic Filtering
Terrain Geocoding
Radiometric Calibration
HH Power Image HV Power Image
[C2] Matrix Elements Processing
Multi-Looking
H/A/Alpha Decomposition
Covariance [C2] Matrix Elements
H A alpha span
Geocoding
σ0HH σ0
HV
SIMPLIFIED PROCESSING CHAIN(basic processing and polarimetric decomposition of FBD343)
- 05 -
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
2008-06-02 2008-07-18 2009-07-21
0 200 400100
Meters0 200 400
MetersDual-pol α/H/span-HSV
(H = alpha / S = entropy / V = span)
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Thatch
Matrix soil
Grass canopy
- 7 -THATCH LAYER EFFECT
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
70
80
90
entropy
alp
haa
ng
le[d
eg
.]
?
2009-07-21
mv = 37.9 / SD = 4.4
2009-07-21
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
70
80
90
entropy
alp
haa
ngle[deg
.]
?
2008-06-02
mv = 34.5 / SD = 3.4
2008-06-02
Alp
ha [d
eg.]
Entropy
Alp
ha [d
eg.]
Entropy
mv = 37.9
SD = 4.4
mv = 34.5
SD = 3.4
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
70
80
90
entropy
alp
haa
ng
le[d
eg
.]
?
2008-05-04
mv = 51.1 / SD = 4.2
2008-05-04
mv = 51.1
SD = 4.2
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
70
80
90
entropy
alp
haa
ng
le[d
eg
.]
?
2007-09-17
mv = 48.7 / SD = 4.9mv = 48.7
SD = 4.9
2007-09-17
GRASSLAND H2α PLANES
Alp
ha [d
eg.]
Entropy
Alp
ha [d
eg.]
Entropy
- 8 -
Cloude, S.R. (2007): “The Dual Polarisation Entropy/Alpha Decomposition: A PALSAR Case Study, “ In Proceedings of PolInSAR 2007.
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
0
000
11 hh
hvhvspanA
hhHERBA AH
HAH
- 9 -EMPIRICAL GRASSLAND PARAMETER MODEL
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
4748.032.169' HERBA
- 10 -GRASSLAND SOIL MOISTURE ESTIMATION
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
SURFACE SOIL MOISTURE DISTRIBUTION 25 75mv [Vol.-%]
Ü
0 10050m
Sigma Nought
mv_20070802
Value
High : 75
Low : 25
Ü
0 10050m
Sigma Nought
Ü
0 10050m
Sigma Nought
mv_20070917
Value
High : 75
Low : 25
2007-08-02 2007-09-17
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Conclusions• L-band dual-pol SAR has the potential to correct for
disturbing effects occurring in grassland ecosystems without
the use of a priori knowledge
• The retrieval algorithm is suitable to account for varying
effects of vegetation and thatch
• The thatch layer is the major source of attenuation
• At L-band the amount of above ground grass biomass and its
geometric properties can be neglected if <2 kg/m²
CONCLUSIONS - 12 -
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Thank you for your attention.
Acknowledgements The authors thank the Japan Aerospace Exploration Agency (JAXA) and the European Space Agency (ESA) for the provision of ALOS PALSAR data through their PI programme (AOALO.3570). Financial support by the SFB/TR32 "Patterns in Soil-Vegetation-Atmosphere Systems" funded by the German Research Foundation (DFG) is gratefully acknowledged.
- 13 -
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
2009-07-21
0 200 400100
Meters0 200 400
MetersDual-pol Pauli-RGB
(R = C22 / G = C11-2xC12r+C22 / B = C11)
Ü
0 10050m
Sig ma Nought
Ü
0 10050m
Sig ma Nought
2009-07-212009-07-21
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
Surface Soil Moisture Distribution 25 75mv [Vol.-%]
Ü
0 10050m
Sigma Nought
mv_20080504
Value
High : 75
Low : 25
Ü
0 10050m
Sigma Nought
mv_20080602
Value
High : 75
Low : 25
Ü
0 10050m
Sigma Nought
mv_20080619
Value
High : 75
Low : 25
2008-05-04 2008-06-02 2008-06-19
Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
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Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
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Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
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Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
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Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
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Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
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Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
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Christian N. KoyamaUniversity of CologneIGARSS 2011Vancouver, July 26
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