Meteorology: Understanding the Atmosphere            Ackerman and Knox



UV Radiation

Ultraviolet radiation (or UV) is electromagnetic energy with wavelengths between .2 and .4 microns. The sun emits UV radiation as well as radiant energy at other wavelengths, such as the visible. UV light has more energy than the visible light emitted by the sun. UV radiation has been classified as three bands or types, based on the wavelength of light:


UV-A (.32 to .4 microns): The amount of UV radiation at the surface remains fairly constant throughout the year. These rays contribute to premature aging of the skin.
UV-B (.28 to .32 microns): These rays, which are more intense then UV-A radiation, are more intense in the summer than winter, increase towards the equator and at higher altitudes. Absorption of UV-B by your skin is the common cause of sun burn.
UV-C (.2 to .28 microns): The most intenand dangerous useuse UV radiation. It is normally absorbed completely by the ozone layer and does not reach the surface.
Your skin and UV Radiation

Exposing your skin to ultraviolet radiation stimulates melanin-producing cells. With increasing amounts of melanin you skin darkens. This tanning provides a protection against UV radiation damage. Prolonged exposure to UV radiation causes the skin to loss its resiliency and over time your skin will begin to look like leather. UV radiation can also activate a cancerous transformation of skin cells.

Basic Forms of Skin Cancer

Your Eyes and UV light

UV Index