Transcript Part I-What is Visibility?

References:
• http://vista.cira.colostate.edu/improve/
• Acidic Deposition:State of Science
and Technology (report 24) 1990
Visibility: Existing and Historical
Conditions – Causes and Effects
• Introduction to Visibility (WC Malm)
issn 0737-5352-40 (CIRA-CSU)
What is Visibility?


Historically visibility was thought of in terms
of the furthest distance one could see a
large black object.
From a scenic vista perspective, there’s
more interest in color, line, texture, and form
of a scenic landscape feature.
How far can you see?
Great Smoky Mountains
National Park
Yosemite National Park
Glacier National Park
Canyonlands National Park
Big Bend National Park
Layered Hazes
Layered Hazes
The Seeing of a Landscape Feature
Relationship Between Aerosols and
Optical Properties
Extinction =
The extinction coefficient is made up of
particle and gas scattering and absorption:
bext = bsg + bag + bsp + bap
where s, a, g, and p refer to scattering,
absorption, gases, and particles, respectively.
Scattering Efficiency (Q)
Single Particle Efficiency
Particle Size Distribution
Scattering Efficiency as Function of
Size
Carbon Extinction Efficiency
Phase Function for Soil and Sulfate
Phase Function for Carbon
Forward and Backward Scattering
On the Nature of Light





Wave-like characteristics of light
Electromagnetic radiation
Photons and color
Why objects are colored
Atmospheric optical effects
IntroVis.exe