1. Color and Spectral Signatures Steve Dutch University of Wisconsin-Green Bay

2. It’s a Colorful World

3. Color and Wavelength

5. Color Formalisms Physical Optics – Scattering is most important in Remote Sensing Color Centers and Crystal-Field Effects – Individual atoms interact with light Inter-Atomic Interactions – Charge transfer – Molecular orbitals – Vibrations Band Theory – Applicable to radar, not much to passive remote sensing

6. Physical Optics Scattering – Particulate Matter Dispersion – Rainbows, etc. Interference – Oil slicks, sea shells Diffraction – Opal, CD’s

7. Scattering

9. Anti-Crepuscular Rays

10. Major Types of Scattering Rayleigh scattering – Small particle compared to wavelength of light Mie scattering – Particle about the same size as wavelength of light Geometric scattering – Particle much larger than wavelength of light

11. Rayleigh Scattering Molecules and nanoparticles Proportional to 1/λ 4 Blue vs. Red = (700nm/400nm) 4 = 9.4 Why the sky is blue Why isn’t the sky purple? – Less sunlight – Lower eye sensitivity – Greater absorption UV Scattering useful in particle studies

12. Mie Scattering Responsible for most white colors Cloud particles Oil droplets in contaminated water Suspended sediment Algal blooms

13. Multiple and Mie Scattering

14. Backscattering

15. Atomic Emission and Absorption

16. Quantum Pinball

17. Fluorescence (Sunlight and laser induced fluoresence in chlorophyll)

18. Phosphorescence

19. Electrons and Light

20. Coloring Agents in Minerals

21. Iron is the Main Source of Color in Rocks and Soils

22. Charge Transfer

23. Electron bumped between atoms Extremely effective absorption mechanism A major reason UV is not very useful for surface remote sensing Very strong UV and blue absorption in iron oxide Why we have “earth tones”

24. Molecular Orbitals

26. Chlorophyll

27. Water Vibration Modes

28. What Color is Water?

29. What Color is Ice?

30. Spectrum of Water