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Mountain shadow phenomena. 2: The spike seen by an off-summit observer
Applied Optics
|March 12, 2010
Summary
The mountain shadow
Area of Science:
- Atmospheric optics
- Geophysics
Background:
- Mountain shadows exhibit an oblique spike or contrast edge when the sun is low.
- This phenomenon is observed by off-summit observers.
Purpose of the Study:
- To explain the optical phenomenon of the oblique spike in mountain shadows.
- To investigate the role of observer position and aerosol illumination in shadow visibility.
Main Methods:
- Analysis of perspective effects based on observer location.
- Investigating contrast effects between illuminated aerosols.
Main Results:
- The oblique spike is a perspective effect dependent on observer position within the shadow.
- Shadow visibility is influenced by contrast between differently illuminated aerosols.
Conclusions:
- The observed shadow edge is an artifact of viewing geometry and atmospheric contrast.
- Numerical simulations confirm the perspective and aerosol contrast mechanisms.
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