1. Illumination Dependent Aerosol Optical Properties n Volume scattering function n Path function n Path radiance n Atmospheric modulation transfer function

2. gainloss Radiation Transfer Equation

3. When N r has some special value, N q, such that b ext N q =, then dN q /dr = 0. N q is independent of r and is commonly referred to as the equilibrium radiance. Equilibrium Radiance

4. If N q is constant, the previous equation can be integrated to yield where Radiance Difference

5. Rearranging yields The second term is the path radiance (airlight),, which results from scattering processes throughout the sight path. The parameter is the sky radiance Path Radiance

6. If T  is approximately zero, then N q = =N s (sky radiance) and: Path Radiance Approximation

7. In general:

8. .. Radiance Difference and Real World

9. Apparent and Inherent Contrast Define: Apparent Contrast: Inherent Contrast:

10. Radiance Difference Transmittance

11. Contrast Transmittance

12. If background is sky then: and

13. If background is sky, N s : Estimating Extinction and, which yields

14. The distance at which C r approaches a threshold contrast of between -0.02 or -0.05 defines the visual range, V r. If  C o  = 1 (black object) and -0.02 is taken to be a threshold contrast, then the previous equation becomes The Visual Range Concept

15. Visibility Metrics n Apparent contrast: C r = C o e -b ext r n Visual Range: vr = 3.912/ b ext n decView: dv = 10 ln(b ext /.01)

18. Contrast Sensitivity Surface (back)

19. Contrast Sensitivity Surface (forward)

20. Forward Scattering

21. Back Scattering

22. Optics of Visibility

23. La Sals –Forward Scattering

24. La Sals – Backward Scattering

25. La Sals -- 30km

26. Mt Trumbull -- 130km

27. North Rim of Grand Canyon Through Smoke Plume

28. Easterly View of Grand Canyon from Desert View Watch Tower

29. Westerly View from Desert View Watch Tower

30. Clouds Evaporate Leaving Sulfate Haze

31. Clouds Evaporated Leaving Sulfate Haze

32. Sulfate Haze Trapped Below Rim

33. Next Day After Haze is Blown Out

34. Path Radiance Absent Because of Clouds

35. Nitrogen Dioxide Haze

36. Nitrogen Dioxide Plume

37. Illumination Effects