1. The document analyzes data from an airborne SAR system called Pi-SAR to classify forests damaged by Typhoon Songda in 2004 using tree height change detection. 2. Amplitude analysis of Pi-SAR data before and after the typhoon achieved 64.1% accuracy in identifying damaged sites. Three-component decomposition analysis achieved 77.7% accuracy. 3. Interferometric SAR processing showed potential for quantitative height change detection between images, but phase unwrapping issues remain and coherence analysis had difficulty distinguishing damaged areas. Fusion with optical data is proposed for future work.

1. Classification of Typhoon-Destroyed Forests Based on Tree Height Change Detection Using InSAR Technology IGARSS 2011 Haipeng Wang 1 , Kazuo Ouchi 2 , and Ya-Qiu Jin 1 1. Key Laboratory of Wave Scattering and Remote Sensing Fudan University, P.R. China. 2. Department of Computer Science National Defense Academy of Japan, Japan.

3. Tomakomai National Forests Shikotsu Lake Larch Todo Fir Red Pine Spruce

4. Pi-SAR Pi-SAR ( P olarimetric i nterferometric - SAR ) is an airborne SAR developed jointly by NICT (National Institute of Information and Communications Technology) and JAXA (Japan Aerospace Exploration Agency). It is equipped with two X-band antennas (frequency 9.55 GHz, wavelength 3.14 cm) and a L-band antenna operating at frequency 1.27 GHz (wavelength 23.6 cm). The nominal resolution is 1.5 x 1.5 m at X-band, and 3 x 3 m at L-band for 4-look azimuth multilooking. L-band antenna X-band main antenna X-band sub-antenna

5. Pi-SAR Data JAXA/NICT L-band colour composite polarimetric Pi-SAR image azimuth range study area Shikotsu Lake Tomakomai City Tarumae Mt. study area Data acquired:7 th , November, 2002 Data acquired:3rd, November, 2004 azimuth range

6. Ground-Truth Biomass Data Collection Field measurements were made in 2002, 2003, 2005, and in 2006. Tree species, height, DBH (Diameter at Breast Height), basal area, soil moisture were measured within a 20 x 20 m sample area in each stands, and converted to above-ground biomass using the conversion formula provided by Project department (Stand volume table -East Japan-, Japan Forestry Investigation Committee. Tokyo: Forestry Agency, Oct. 1998)

7. Typhoon Songda Typhoon Songda (Japanese No.18) Duration:August 28 – September 8 Typhoon Songda killed 20 people and injured 700 others in Japan. In addition, 15 crew members of a vessel were reported missing. Damages from the storm amounted to $7.17 billion (2004 USD) Time arrived at Tomakomai: September 7th, 2004

8. Fallen Trees After Typhoon

9. Ground-Truth Data

10. Amplitude Analysis Test sites Whole image Image No. HH HV VV L6407 67.1119 64.3982 66.1515 L8104 66.6437 64.4475 66.7929 L6407-L8104 0.4682 -0.0493 -0.6414 Site No. HH subtraction HV subtraction VV subtraction 196 0.8403 0.6001 -0.2851 197 0.9535 0.5802 -0.2825 198 0.8714 0.3279 -0.5437 217&218 0.8619 0.4444 -0.2188 243 0.8975 0.4549 -0.2435 245 0.9827 0.3009 -0.2797 267 0.9856 0.4899 -0.0584 271 0.8962 0.4392 -0.5062 300 0.8269 0.4759 -0.0099 302 0.7889 0.3169 -0.2331 268 0.6641 0.0218 -0.4429 303 0.5009 -0.0223 -0.6568

11. Amplitude Analysis Results Accuracy:64.1%

12. Scattering Mechanisms From Forests sc attering from crown parts surface scattering from ground multiple reflection betw een ground and tree trunks/branches multiple/volume scattering from branches X/C-bands L/P-bands

13. Three-Component Decomposition Analysis A. Freeman and S. L. Durden, “A three-component scattering model for polarimetric SAR data,” IEEE Trans. Geosci. Remote Sens. , vol. 36, no. 3, pp. 936–973, May 1998. Site No. Double subtraction Volume subtraction Surface subtraction 196 14.1248 1.1277 -22.1597 197 38.2798 1.0917 -39.4679 198 39.1910 0.4771 -34.9405 217&218 35.4332 0.7719 -32.1722 243 37.5858 0.7808 -34.0847 245 37.6906 0.4519 -25.9017 267 37.1895 0.9402 -32.4539 271 28.2527 0.8799 -27.4304 300 31.7851 0.8673 -31.1892 302 35.5875 0.4366 -27.3383 268 32.7751 -0.1122 -17.6746 303 33.6438 -0.2045 -27.5287 Double Volume Surface L6407 102.0232 138.2508 63.4812 L8104 74.4862 138.4537 83.7599 L6407-L8104 27.5449 -0.2026 -20.2847

14. Scattering Mechanism Analysis Result Accuracy:77.7%

15. Pi-SAR L-band antenna X-band main antenna X-band sub-antenna Pi-SAR on Gulf Stream II X-band and L-band radomes Two antennas within X-band main radome Partial Pol-InSAR by X-band main radome (Sub-antenna data not acquired this time)

16. Pi-SAR Data for Interferometric Analysis X-band VM Pi-SAR image Data acquired:3 rd , August, 2004 Data acquired:3rd, November, 2004

17. M , N —— Moving window size S —— Data Complex Interferogram Complex Degree of Coherence

18. Phase Image

19. Removal of Orbital Fringes Court esy of Dr. Moriyama X7904 X8104

20. Phase Unwrapping(X7904)

21. Phase Unwrapping(X8104)

22. Height Change

23. Conclusions and Future Work Research was carried out to extract information of typhoo-damaged forests. The accuracies of 64.1% and 77.7% were obtained for amplitude and decomposition data respectively. InSAR processing resutls show it’s potential, but there is no quantitative results yet. Phase unwrapping: other approaches rather than the branch cut. Difficult to see the difference of typhoon-damaged information from the coherence data before and after the typhoon. Next step is to exam the coherence before and after the typhoon Fusion of optical data and SAR data: QuickBird, IKONOS, Geoeye multispectrum optical data, Pi-SAR I&II data.