WW2010
University of Illinois

WW2010
 
welcome
 
online guides
 
archives
 
educational cd-rom
 
current weather
 
about ww2010
 
index

Online Guides
 
introduction
 
meteorology
 
remote sensing
 
reading maps
 
projects, activities

Meteorology
 
introduction
 
air masses, fronts
 
clouds, precipitation
 
el nino
 
forces, winds
 
hurricanes
 
hydrologic cycle
 
light, optics
 
midlatitude cyclones
 
severe storms
 
weather forecasting

Light, Optics
 
introduction
 
mechanisms
 
air, dust, haze
 
ice crystals
 
water droplets

mechanisms
 
reflection
 
scattering
 
refraction
 
diffraction

Scattering
 
selective
 
mie

User Interface
 
graphics
text

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Selective Scattering
better at scattering certain wavelengths than others

Scattering is a rapid process whereby light is actually absorbed by a particle and then quickly emitted in another direction.


Scattering particles can be air molecules, dust particles, water droplets or pollutants, which scatter incoming sunlight (or moonlight) in all directions, similar to how a pinball bounces around in a pinball machine. During the scattering process, no energy is lost or gained, so no temperature changes occur.

[Image: a blue sky (65K)]
Photograph by Ron L. Holle


Selective scattering occurs when certain particles are more effective at scattering a particular wavelength of light (Rayleigh scattering). Air molecules (oxygen and nitrogen, for example) are small in size, and thus more effective at scattering shorter light wavelengths (blue and violet), producing blue skies visible on a clear sunny day.

[Image: colorful sunset (50K)]
Photograph by Ron L.Holle


When the sun is low on the horizon and the atmosphere is loaded with particles, only longer wavelengths of light (yellow and red) are able to penetrate the dense atmosphere. Other wavelengths of visible light are simply scattered away and never reach our eyes, producing in a colorful sunset at the end of the day.


Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.