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+1010Ground Range Resolution: 15 mCenter Frequency: L-band @ 1,270 MHzChirp Bandwidth: 14 MHzPolarization: HH + HVOff-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 moistureSurface roughnessBiomass
ALOS PALSAR FBD343 DATA(product description & acquisition overview)
- 04 -
Jan.
Feb. Mar. Apr. May
June July
Aug.
Sep.
Oct. Nov.
Dec.
Aug.
Sep.
Oct. Nov.
Dec.
Jan.
Feb. Mar. Apr.
May
June July
Aug.
Sep.
Oct. Nov.
Dec.
Jan.
Feb. Mar. Apr.
May
June
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 400100Meters
0 200 400Meters
Dual-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
alph
aangl
e[deg
.]
?
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
alph
aangl
e[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
alph
aangl
e[deg
.]
?
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
alph
aangl
e[deg
.]
?
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 Noughtmv_20070802Value
High : 75
Low : 25
Ü
0 10050m
Sigma Nought
Ü
0 10050m
Sigma Noughtmv_20070917Value
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 400100Meters
0 200 400Meters
Dual-pol Pauli-RGB(R = C22 / G = C11-2xC12r+C22 / B = C11)
Ü
0 10050m
Sig ma Nou ght
Ü
0 10050m
Sig ma Nou ght
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 Noughtmv_20080504Value
High : 75
Low : 25
Ü
0 10050m
Sigma Noughtmv_20080602Value
High : 75
Low : 25
Ü
0 10050m
Sigma Noughtmv_20080619Value
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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