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TULSA, Okla. — The UV Index tells us the ground-level intensity of ultraviolet (UV) radiation. There are multiple factors that lead to this multi-step calculation, resulting in a simple number ranging from 1-11. This calculation is made by the U.S. National Weather Service, and with technology developing further, a portion of this data is pulled from computer models. Any guesses on which factors matter the most?
- Ozone levels. The ozone layer effects UV radiation at ground-level because it tends to absorb ultraviolet radiation. Ozone also is naturally thinner in the tropics as compared to the mid- and high-latitudes, so there is less ozone to absorb the UV radiation as it passes through the atmosphere.
- The Angle of the Sun. The sun’s rays are strongest at the equator where the sun is most directly overhead and where UV rays travel the shortest distance through the atmosphere. This varies seasonally as the placement of the sun changes throughout the year. This can also be noticed day to day with the sun being highest in the early afternoon.
- Cloud cover. Clouds tend to absorb UV radiation from the sun, and the more it absorbs, the less UV radiation we encounter at ground-level. Using this helps us determine the accurate adjustment for each respective data point.
- Last but not least, elevation! The closer we are to the sun, the higher the UV radiation. On average, the UV intensity increases approximately 6% per kilometer elevation. For example, the UV intensity is higher at the top of the BOK tower than it is at the Gathering Place!
After a few more calculations, the result of these factors is a number ranging from 1 to 11. This range is called the UV Index Range.
Why is it important to measure the UV Index? Ultraviolet radiation can be dangerous to our skin depending on the intensity. Studies have shown cases of harmful sun burns and even skin cancer as a result of UV Indices exceeding 8. As the UV Index increases, it is crucial to know when to set the timer when spending time outside this summer.
How can you reduce the risk of skin damage?
- Always check the UV Index. If the UV Index is 10, the burn time is as little as 10-15 minutes. Knowing how long to set your timer for when going outdoors will keep you safe while soaking in a healthy amount of sun.
- Use sunscreen! Sunscreen protects over 90% of UV intensity, which will keep you safe and outside enjoying the pool!
For more information on UV radiation, go to https://www.weather.gov/rah/uv to find the UV Index Range, forecast, and further information.
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