Earth's sunniest spot feels just like summer on Venus, says new study

Explaining this phenomenon, Seiji Kato, an atmospheric scientist at NASA who was not involved in the study, told The Washington Post that high-altitude locations above the water vapor layer and with fewer clouds and aerosols inevitably receive more sunshine.

The study highlights an atmospheric observatory, established in 2016 on the Chajnantor Plateau in Chile, dedicated to studying sunlight reaching the Earth's surface and atmospheric composition.

It notes that over the first five years of measurements, the Altiplano region received the highest-known amount of sunlight on Earth, averaging 308 watts per square meter—the highest worldwide.

Moreover, sunlight on the Altiplano becomes incredibly intense during cloud break-ups, reaching up to 2,177 watts per square meter. This intensity is comparable to sunlight at approximately 0.79 astronomical units from the Sun.

Lead study author Raul Cordero, a climatologist at the University of Groningen, Netherlands, revealed the astonishing comparison: standing on Venus during its summer would be akin to experiencing this intense radiation.

"It's actually the radiation that you will be receiving in summer if you are standing up on Venus," he said.

Cordero added that the comparison is "incredible" since Venus is approximately 28 percent closer to the Sun than Earth.

The authors also discovered these extreme variations in sunlight occur more frequently, with greater intensity and duration, on the Chajnantor Plateau than anywhere else in the world.

They emphasized Altiplano's unique attributes make it an excellent location for studying how photovoltaic (solar) power plants respond to periods of intense sunlight.

The complete study was published in AMS and can be found here.

Study abstract:

Satellites have consistently pointed to the Altiplano of the Atacama Desert as the place on Earth where the world’s highest surface irradiance occurs. This region, near the Tropic of Capricorn, is characterized by its high elevation, prevalent cloudless conditions, and relatively low concentrations of ozone, aerosols, and precipitable water. Aimed at studying the variability of the surface solar irradiance and detecting atmospheric composition changes in the Altiplano, an atmospheric observatory was set up in 2016 at the northwestern border of the Chajnantor Plateau (5,148 m MSL, 22.95°S, 67.78°W, Chile). Here, we report on the first 5 years of measurements at this observatory that establish the Altiplano as the region that receives the highest-known irradiation on Earth and illuminate the unique features of surface solar extremes at high-altitude locations. We found that the global horizontal shortwave (SW) irradiance on the plateau is on average 308 W m−2 (equivalent to an annual irradiation of 2.7 MWh m−2 yr−1, the highest worldwide). We also found that forward scattering by broken clouds often leads to intense bursts of SW irradiance; a record of 2,177 W m−2 was measured, equivalent to the extraterrestrial SW irradiance expected at approximately 0.79 astronomical units (AU) from the Sun. These cloud-driven surface solar extremes occur on the Chajnantor Plateau at a frequency, intensity, and duration not previously seen anywhere in the world, making the site an ideal location for studying the response of photovoltaic (PV) power plants to periods of enhanced SW variability.