The Altiplano sits high above Chile’s Atacama Desert, near the Tropic of Capricorn and the Andes mountains towards the South American west. It’s a cloudless place, above water vapour level at 4000 metres altitude. Levels of ozone and aerosols are low, while solar irradiance (the Sun’s energy emitted to Earth) is high.
These conditions, according to a study published by the American Meteorological Society (AMS) make it the sunniest place on Earth. They also make the Altiplano one of the only places on Earth where sunlight intensity is comparable to Venus. Venus is 28% closer to the sun than Earth is.
Why is this important? The study’s authors point out that understanding Earth’s own extremes of surface solar conditions can drive development and power efficiency when it comes to solar energy potential.
1. The study
In 2016 an atmospheric observatory was established on the northwestern border of Chile’s Chajnantor Plateau. Its mission was to study the atmospheric conditions and sunlight reaching the Earth’s surface.
Over the next five years, the observatory recorded that more sunlight reached the Altiplano (308 watts per square metre on average) than any other place on the planet. At its highest during cloud break-ups, it reached an astonishing 2,177 watts per square metre.
2. Venus
The Altiplano has a prevalence of thin, breaking cloud which acts not as a shield but as a magnifying glass for the sun’s rays, increasing solar radiation on the surface by up to 80 percent (compared to cloudless conditions).
It’s actually the radiation that you will be receiving in summer if you are standing up on Venus.
Raúl Cordero, scientist
Cordero acknowledged the dangers of exposure. “If you are exposed to such a high radiation danger, you have to protect your skin,” he said. “At this particular location, for people working there … they are aware that the radiation was high, but now we know how really high.”
3. Applications
The study also reported more frequent extreme variations of sunlight on Chajnantor Plateau than anywhere else worldwide. Sunlight intensity and duration were notable, creating solar energy potential averaging approximately double that of Central Europe and the U.S.A’s East Coast.
The particularly volatile conditions, according to the research team, mean the Altiplano, the second highest extensive plateau on Earth, could become an important test ground for working out how photovoltaic (solar) power plants cope with periods of intense sunlight.
