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

ice crystals
 
halos
 
sundogs
 
sun pillars

User Interface
 
graphics
text

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Sun Pillars
vertical shafts of light

A sun pillar is a vertical shaft of light extending upward or downward from the sun. Typically seen during sunrise or sunset, sun pillars form when sunlight reflects off the surfaces of falling ice crystals associated with thin, high-level clouds (like cirrostratus clouds).

[Image: a sunpillar (68K)]
Photograph by: Rauber

The hexagonal plate-like ice crystals fall with a horizontal orientation, gently rocking from side to side as they fall.

When the sun is low on the horizon, an area of brightness appears in the sky above (or below) the sun as sunlight is reflected off the surfaces of these tipped ice crystals.



sundogs
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.

water droplets