Online enyclopedia and dictionary of weather terms for the school classroom or college. Book quality descriptions that make the science of meterology understandable, even to kids
HOME CLOUD/PRECIP FCST MOVIE TEMPERATURE FCST MOVIE 2007 HURRICANES
NATIONAL RADAR WATCHES & WARNINGS STORM REPORTS 2008 HURRICANES

What causes halos?
halo at the South Pole (photo: NOAA)
Haloes are usually caused by the refraction of sunlight (or moonlight) as it passes through cirrus clouds. The ice particles in the cirrus clouds that produce these beautiful displays are almost always in the shape of hexagonal plates or columns. As these ice crystals fall, they often have a preferred orientation, which also affects the kind of halos and arcs that are displayed. Most halos are positioned at an angular distance of 22 degrees from the sun. As in the photograph above, parhelia ("sun dogs") are often seen on the right and left sides of the main halo, and an "upper tangent arc" is sometimes seen at the top of halo. In-depth descriptions of a wide variety of atmospheric optical phenomena, including stunning photographs and computer simulated images of the various kinds of halos, can be found here.

Dr. Roy W. Spencer:
GLOBAL WARMING: Manmade or Natural?


Now IN-STOCK at Amazon.com:
CLIMATE CONFUSION:
How Global Warming Hysteria Leads to Bad Science,
Pandering Politicians, and Misguided Policies that Hurt the Poor




Get your Weather,
without the annoying popups,
from
by ZIP code or City, State    
WeatherQuestions.com home
Copyright© 2007 WeatherStreet