Tjuatja_IGARSS-11_prez.pptx

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Tjuatja_IGARSS-11_prez.pptx

  1. 1. BACKSCATTERING  FROM  SEA  SURFACE  WITH  PRECIPITATION<br />Saibun Tjuatja, Li Jiamei, Dong Xiaolong<br />Wave Scattering Research CenterThe University of Texas at Arlington&Chinese Academy of Sciences Center for Space Science and Applied ResearchMicrowave Remote Sensing Laboratory<br />July 25, 2011<br />This work is supported in parts by the Chinese Academy of Sciences Visiting Professorships for Senior International Scientists Program<br />
  2. 2. Objectives of this study<br />A physics based backscattering model that accounts for the vertical profile of the rain column<br />Quantitative link between geophysical parameters and backscattering measurements<br />
  3. 3. 94 GHz Radar Reflectivity and Doppler Velocity from CRS measurements (Li et al., 2004)<br />
  4. 4. Physics Based Forward Modeling:Microwave scattering from sea surface with precipitation<br />Physical Parameters<br />Model Parameters<br />Physical Structure<br />Model Structure<br />
  5. 5. A Scattering Model for an Inhomogeneous Layer with Vertical Profile<br />
  6. 6. Rain Layer Parameters<br />Vertical profile<br />modeled with 12 sublayers<br />Rain rate:<br />10.48 mm/h and 22.80 mm/h<br />Drop size distribution:<br />average drop size<br />volume fraction<br />Drop shape: spherical<br />
  7. 7. Vertical Profile (Average Drop Size) of Rain Column<br />profile A:<br /> R = 10.48 mm h-1<br />Volume fraction:<br /> 0.7500E-05<br />profile B: <br /> R = 22.80 mm h-1<br /> Volume fraction:<br /> 0.8000E-05<br />
  8. 8. Rain Rate<br />where<br />
  9. 9. Drop Size Distribution<br /> Gamma distribution:<br />Volume fraction of rain drops:<br />
  10. 10. Other Model Parameters<br />Sea surface roughness (IEM model)<br />Rain drop relative permittivity (at 13.6 GHz):<br />
  11. 11. Model Analyses<br />Effects of precipitation at C- and Ku-Band<br />Effects of rain rates<br />Effects of drop average drop size at constant R<br />Effects of volume fraction with a constant average drop size<br />Effects of snow & melting layer<br />
  12. 12. Effects of Precipitation (R=10.48mm h-1 ) at C- and Ku-Band<br />
  13. 13. Effects of Rain Rate<br />
  14. 14. Effects of Drop Size with Constant R<br />
  15. 15. Effects of Volume Fraction with a Constant Drop Size<br />
  16. 16. Vertical Profile with Snow & Melting Layer<br />
  17. 17. Effects of snow & melting layer<br />
  18. 18. Summary & Conclusion<br />A scattering model for rain column above sea surface which accounts for vertical profile was developed and qualitatively validated.<br />Model analyses show that at R=10.48 mm/h, the effects of precipitation at C-Band is negligible at small incident angles <br />At Ku-Band, key features for differentiating backscattering from sea surface with and without precipitation include:<br />angular trend <br />separation between VV and HH<br />
  19. 19. Thank you<br />

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