FR3.TO5.4.pptx
- 1. IGRSS 2011, Vancouver , CandaRETRIEVING BRDF OF DESERT USING TIME SERIES OF MODIS IMAGERYHaixia Huang, Bo Zhong, Qinhuo Liu, and Lin SunPresented by Bo [email protected] of Remote Sensing Applications, Chinese Academy of Sciences
- 3. Methodology
- 5. Applicatoins
- 6. Conclusions Background BRDF is the key parameter for:
- 9. More
- 10. Desert is one of the main landcover types
- 11. Strongly reflecting the solar radiation
- 12. More Problem There is no “good” BRDF product of desert
- 13. Methodology-flowchartMODIS imageryConverting DN to TOA reflectanceIdentifying the “clearest” of each observationsLookup TablesRetrieving reflectance of “clearest” observationsFitting to Staylor-Suttles BRDF modelBRDF of desert
- 14. Methodology- site choosingCole view of the site(TM imagery color composite)Location of the experimental site(MODIS imagery color composite)
- 15. Methodology- site choosingIt is stable, so it can be seen as an invariant object;
- 16. There are a lot of lakes within the calibration site, which are seldom polluted, so the lowest AOD of calibration site can be determined by Dark Object (DO) method using Landsat TM and ETM+ data.8Methodology- site choosing（a）Mar. 3, 2000（b）Feb. 3, 2010
- 17. AOD retrieval using DO method
- 18. Original methodIdentifying clear pixelsTime series of MODIS imageryReflectance of clear pixelsBRDF fittingLUTReflectance of hazy pixelsAOD of hazy pixelsMODISsurface reflectance
- 19. Modifications for the original methodAOD determination for the “clearest” days;
- 20. Shrinking the use of the algorithm from globe to the desert calibration site, which is stable;
- 21. Identifying the “clearest” observations for every 10 degrees in view zenith angles from 0-50 degree (0-10, 11-20, 21-30, 31-40, and 41-50);
- 22. Using Staylor-Suttles BRDF model instead of Walthall BRDF.Preliminary resultsMODIS-B3: Staylor-Suttlescoefficients
- 25. Comparison with MODIS products
- 26. R2 much higher
- 27. RMSE is lowerApplications I: inter-calibration of AVHRR using retrieve BRDFSpectral matching of AVHRR and MODIS
- 28. AVHRR data simulation using the new method
- 32. Applications II: global desert BRDF retrievalMapping of the desert
- 33. BRDF and AOD retrieval simultaneously using the new method
- 34. Preliminary validationThe chosen desert sites
- 35. The geolocations of the deserts
- 38. Lybia desert
- 39. Saharadesert
- 40. ConclusionsThe new method is able to catch the BRDF characterization of deserts
- 41. This method can be used for inter-calibration of reflective bands of moderate satellite data like AVHRR
- 42. This method is helpful for researches on earth radiation budgetThank you for your attention!