1. Estimationg rice growth parameters using X-band scatterometer data
IGARSS2010, Honolulu Hawaii, July 25-30, 2010
Estimationg rice growth parameters using X-band scatterometer data
Yihyun Kim1*, S.Young Hong1, Eunyoung Choe1 and Hoonyol Lee2
1 National Academy of Agricultural Science, RDA, Korea
2 Department of Geophysics, Kangwon National University, Korea

2. Contents
Background 1 2 3 4
Material and Methods
Results
Conclusion

3. Background Rice is one of the major crops in Korea
Microwave radar can penetrate cloud cover regardless of weather condition
Ground-based polarimetric scatterometer has advantage of monitoring crop
conditions with full polarization and various frequencies
Plant parameters such as LAI, biomass, plant height are highly correlated with
backscattering coefficients
ENVISAT SAR data (5.3 GHz, hh-, hv-polarizations, and incidence angles
between 28.5° and 40.9°) to monitor rice growth and compared the data with
simulation results (Le Toan et al, 1997)

4. Background
RADARSAT data (5.3 GHz, hh-polarization, and incidence angles between
36° and 46°) was analyzed for monitoring the rice growth in Korea (Hong et al,2000)
Backscattering coefficients from a ground scatterometer are often affected by
weather condition the necessity of near-continuous automatic measurement
has arisen by the experiment in 2007 (Kim et al, 2008)

5. Objective
To analyze scattering characteristics of paddy rice obtained from
L, C, X-band automatic scatterometer system
Relationship between backscattering coefficients in L, C, X-band
and plant parameters with full polarization
Prediction of rice growth parameters using backscattering
coefficients in L, C, X-band

6. Study site - An experimental field at NAAS, Suwon, Korea
Testing varieties : Chuchoungbyeo
The size field : 660m2

7. Materials and Methods L, C, X-band automatic scatterometer system
C-band
L-band
Measurement Interval : 1 per 10 minutes

8. Dual polarimetric horn
Materials and Methods
Specification of the L, C, X-band automatic scatterometer system
Specification
L-Band
C-Band
X-Band
Center frequency
1.27GHz
5.3GHz
9.65GHz
Bandwidth
0.12GHz
0.6GHz
1GHz
Number of frequency points
201
801
1601
Antenna type
Dual polarimetric horn
Antenna gain
12.4dB
20.1dB
22.4dB
Range resolution
1.25m
0.25m
0.15m
Wavelength
0.23m
0.056m
0.031m
Polarization
HH, VV, HV, VH
Platform height
4.16m

9. Radar backscattering measurement
- Between before transplanting(17 May, 2009) and harvesting stage(12 Oct, 2009)
Growth data collection
- Leaf Area Index, Plant height, Fresh and Dry weight etc.
Transplant stage (mid-May)
Panicle formation stage (mid-July)
Heading stage (mid-Aug)
Harvesting stage (mid-Oct)

10. Backscattering coefficients of X-band the follow expression
Calculation of backscattering coefficients
(apply to radar equation)
Backscattering coefficients of X-band the follow expression

11. Results Temporal variations in growth parameters during rice growth
heading stage
<Plant height>
<Leaf Area Index>

12. Results Temporal variations in growth parameters during rice growth
heading stage
<Fresh biomass>
<Dry biomass>

13. Results
Temporal variations of backscattering coefficients at polarization and
incident angle 45° for the L-band
booting stage ~ heading stage
(most active rice growth period)

14. Results
Temporal variations of backscattering coefficients at polarization and
incident angle 45° for the C-band

15. Results
Temporal variations of backscattering coefficients at polarization and
incident angle 45° for the X-band

16. Results
Relationship between backscattering coefficients at L, C, X-band and plant variables
L-band VV HH HV
Incident angle
Plant
Height
LAI
Tfw
(g/m2)
Gdw
height 45
0.80**
0.91***
0.90***
-0.78**
0.89***
0.98***
0.96***
-0.74**
0.79**
0.93***
-0.62*
C-band VV HH HV
Incident angle
Plant
height
LAI
Tfw
(g/m2)
Gdw 45
0.60*
0.86**
0.75**
-0.78**
0.70**
0.92***
0.83**
-0.83**
0.77**
0.91***
0.89***
-0.72**
X-band VV HH HV
Incident angle
Plant
height
LAI
Tfw
(g/m2)
Gdw 45
0.63*
0.66*
0.73**
0.94***
0.72**
0.81**
0.84**
0.79**
0.68*
0.83**
0.70*

17. Results Optimum condition for estimation of rice growth parameters
Band
Polarization R2
Plant height(cm)
L-band HH
R2=0.86***
Leaf Area Index
R2=0.96***
Fresh Biomass(g/m2)
Above ground
R2=0.94***
Grain
X-band VV
R2=0.91***
Grain dry weight(g/m2)

18. Results
Prediction of Leaf Area Index using backscattering coefficients(L-band, HH)
y = x
R2 = 0.95***
RMSE =

19. Results
Prediction of Biomass using backscattering coefficients (L-band, HH)
y = x –
R2 = 0.95***
RMSE =

20. Results
Prediction of Grain dry weight using backscattering coefficients (X-band, VV)
y = x –
R2 = 0.96***
RMSE =

21. Conclusions
Backscattering coefficients of rice crop were investigated with an automatically
-operating ground-based scatterometer
The temporal variations of the backscattering coefficients of the rice crop at
L, C, X-band during rice growth period
HH-polarization backscattering coefficients higher than VV-polarization
backscattering coefficients after effective tillering stage(mid-June)
Relationships between backscattering coefficients and the rice growth parameters
Biomass, LAI was correlated with HH-backscattering coefficients in L-band
X-band was sensitive to grain maturity at near harvesting season
Prediction of rice growth parameters using backscattering coefficients in
L, C, X-band 21

22. Thank You !