The rising surface temperature on Earth is usually associated with the depletion of the ozone layer in the atmosphere, which allows ultraviolet radiation to pass through. However, the highest levels of UV radiation ever recorded on the planet did not happen in Antarctica, where the ozone layer holes are found.
How the Highest UV Index Ever Was Detected
The highest UV index ever recorded was 43.3, setting a world record on December 29, 2003. It was detected at the top of the Licancabur Volcano in the Andes mountain range in South America. The extreme measurement was recorded after a radiation detector placed on the 5,920-meter peak caught the UV-B radiation during the summer in the Southern Hemisphere.
This measurement was discovered during research led by planetary scientist Nathalie Cabrol from the SETI Institute in Mountain View, California. Cabrol works as the director of the Carl Sagan Center, where she leads the search for signs of microbial life on planet Mars.
In the 2000s, Cabrol and her colleagues conducted a NASA-funded project to explore the high-elevation lakes in the Andes. They came across Licancabur Volcano, whose summit lake resembles the Gusev Crater on Mars. The team's main goal was to look for signs of life that can thrive in harsh environments resembling the red planet. Instead, their instruments detected considerable UV even after years of fieldwork completion.
According to Cabrol, the highest UV index ever recorded from Licancabur Volcano is higher than the routine measurement in the high Andes, just above the mid-20s. A UV index of 43 is not a typical condition here on Earth, and it is more similar to the amount of UV radiation on the surface of Mars. Days before the record high, the radiation monitoring tool dosimeter revealed that UV-B levels were in the 20s and hit the 30s in January 2004.
In a separate study, scientist Richard McKenzie from the National Institute of Water and Atmospheric Research in New Zealand also discovered that UV index levels above 25 are regularly achieved in the high Andes in Chile and Peru. Argentina and Bolivia.
In the Andes, receiving UV radiation to record heights is due to various factors such as high elevation, intense tropical sun, and naturally low ozone levels. However, models of atmospheric conditions in December 2003 reveal a strange combination of factors that plunged the ozone levels.
Experts believe that the depletion of the protective ozone layer in the region is due to the seasonal thunderstorms and forest fires in the Amazon coupled with the atmospheric train of chemicals from Antarctica. Two weeks before recording the highest UV index, an enormous solar flare was released from the Sun, which could have affected the atmosphere's chemistry and damaged some ozone layers.
What is UV Index?
The Sun produces energy known as ultraviolet radiation which can reach a person either directly, scattered from the open sky, or as reflected by the environment. The level of radiation that a person can receive depends on several factors, such as the time of the day, season of the year, and cloud cover.
UV Index measures the level of UV radiation created to help a person make an informed decision about the amount of time that should be spent under the sun. A higher UV index means that the radiation has a greater potential to damage the skin and eyes in less time. A reading of 11 or more means that unprotected exposure to the sun can be hazardous, and all precautions must be taken, or else the skin and eyes can burn in minutes.
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