The UV index: definition, distribution and factors affecting it

Area of Science:

• Environmental Science
• Atmospheric Science
• Public Health

Background:

• Growing concerns over ozone depletion led to the UV Index's introduction in Canada in 1992.
• The World Meteorological Organization and World Health Organization adopted it as a standard in 1994.
• The UV Index quantifies ultraviolet radiation levels for public guidance and scientific research.

Purpose of the Study:

• To provide an overview of the UV Index.
• To describe its geographical distribution.
• To explain factors influencing UV Index values.

Main Methods:

• UV Index values are determined using ground-based spectrometers and radiometers.
• Radiative transfer models estimate UV Index from ozone and cloud data.
• Satellite measurements of atmospheric ozone and cloud cover are also utilized.

Main Results:

• Mean summer noontime UV Index ranges from 1.5 in the Arctic to 11.5 in southern Texas.
• UV Index can reach 20 at high elevations in Hawaii.
• Forecasts are widely available for public use.

Conclusions:

• The UV Index has become a crucial parameter for characterizing solar UV radiation since 1992.
• It serves as a vital tool for public health, aiding in the avoidance of excessive UV exposure.
• Understanding UV Index factors is essential for accurate assessment and forecasting.