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Leaf Reflectance & Absorption

Leaf Reflectance & Absorption. Reflectance  = 1.0 - Absorption . Transmission  transient--if not absorbed  then reflected . 5880 K. Leaf Spectral Reflectance. Reflectance  = 1.0 - Absorption . Specular versus Diffuse Reflectance. Black Spruce Forest. Backward Scatter View.

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Leaf Reflectance & Absorption

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  1. LeafReflectance & Absorption Reflectance = 1.0 - Absorption Transmission transient--if not absorbed then reflected 5880 K

  2. LeafSpectral Reflectance Reflectance = 1.0 - Absorption

  3. Specular versus Diffuse Reflectance

  4. Black Spruce Forest Backward Scatter View Forward Scatter View

  5. Soil Backward Scatter View Forward Scatter View

  6. Soybean Field Backward Scatter View Forward Scatter View

  7. Bidirectional Reflectance ofBlack Spruce & Jack Pine no shadows in shadow

  8. Maple & Pine reflectancel maple pine

  9. Plant Pigments So, what absorbs in functioning leaves? (Reflectance = 1.0 - Absorption

  10. Liquid Water Absorption Reflectance = 1.0 - Absorption Liquid water in plant leaves completes the absorption picture: leaves must be hydrated for photosynthesis

  11. Leaf Reflectance & Absorption If no absorption, photons can be reflected internally &/or refracted between air (1.0) & hydrated cells (1.33)

  12. Photosynthesis Action Spectrum

  13. Leaf Photosynthesis Piers Seller’s PAR Diagram

  14. Spatial Resolution -- size (1 m, 10 m, 1km) Spectral Resolution -- wavelength(s) Radiometric Resolution -- detail (1oC) Temporal Resolution -- how often Vegetation Remote Sensing

  15. Spectral intervals for studying vegetation--which ones & why nformation all locales, all conditions, etc. vegetation is goal !vive photosynthesis! reduce atmospheric effects to minimize errors Avoid redundancy --keep it simple stupid

  16. In situ measurements at Pawnee National Grasslands, Colorado

  17. Nondestructive Biological Mass (or biomass) Objective Grassland system -- simple, >>herbaceous Plant biomass is source of energy for system Anything is better than clipping!!! Clipping is limited for time & space extrapolations

  18. Spectrometer mini-computer combo

  19. HP-2100 mini-computer data collection system (circa 1971) 8196 bytes of RAM no disk drive Paper tape input/output 2-step/pass Fortran compiler Control panel assembly language operation Teletype used to punch paper tapes Believe it or not--this was state of the art!

  20. Thorough documentation of every plot, before & after clipping

  21. Summary of r2 values vs. l for visible, a close association of regression significance between reflectancel and leaf water content with chlorophyll a & b (leaf water  live veg.)

  22. Ir/red ratio and normalized difference vegetation index

  23. 50% live & 50% deadleaves in plant canopy

  24. Ir/red ratio and normalized difference vegetation index [(ir-red)/(ir+red)]

  25. All dead leaf biomass--no pigments remain

  26. [(ir-red)/(ir+red)] aka ndvi

  27. Winter wheat total dry matterSndvi over growing seasonndvi-days

  28. Winter wheat “harvest”

  29. Winter wheat grain yieldSndvi over growing seasonndvi-days

  30. Sndvi vs. dry biomass Sum ndvi x days

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