Geoingeniería: estudio sobre el impacto de los eclipses en las nubes trae nuevos desafíos a la modificación del clima

Study reveals that cumulus clouds dissipate quickly during eclipses. This effect could have implications for climate engineering that seeks to use aerosols to reflect sunlight and cool the Earth.

eclipse, clouds
Is it really effective to block out the Sun to cool the planet?

A study reveals that during a solar eclipse, clouds disappear quickly, even during a partial eclipse, according to researchers from TU Delft and KNMI. Until now, satellite measurements during these events were unreliable, but a new method has allowed this data to be recovered.

Despite centuries of study on the effects of eclipses, the exact way clouds react to rapid changes in light is largely unknown. This is because geostationary satellites, which orbit the Earth, offer a solution to observe large areas of clouds continuously on a typical day. However, during a solar eclipse, traditional satellite algorithms cannot correctly interpret the decrease in sunlight, resulting in "dark spots" on cloud maps.

Researchers have now managed to restore satellite measurements during solar eclipses by accurately calculating the percentage of the Sun that is obscured, for each place and time on Earth.

"From Earth, you can count clouds and watch them disappear, but that only provides anecdotal evidence," explains Ph.D. Victor Trees. "Even without a solar eclipse, the clouds are constantly changing." Now, researchers have managed to restore these measurements by precisely calculating the percentage of solar dimming for each location and time on Earth.

This study has important implications for climate engineering proposals that seek to cool the Earth artificially by injecting aerosols into the atmosphere or placing solar screens in space. These strategies, while theoretically viable, could create an artificial solar eclipse and therefore affect cloud formation.

The rapid disappearance of clouds during a solar eclipse suggests that this type of intervention could have unwanted side effects on the cloud cycle.

"If in the future we eclipse the Sun with technological solutions, this could affect the clouds," explains Víctor. " Fewer cloud numbers could partly offset the desired effect of climate engineering, because clouds reflect sunlight and therefore help cool the Earth." Additionally, clouds influence local precipitation patterns, underscoring the importance of investigating the potential drought effects of artificial cloud shading.

The sensitivity of clouds

In cloud maps recovered from three solar eclipses over Africa, researchers saw that cumulus clouds began to disappear on a large scale starting at just 15% solar dimming . Once the solar eclipse is over, the cumulus clouds return. On days when there is no solar eclipse, this behavior in cloudiness does not occur.

Cumulus clouds above Earth are particularly sensitive to eclipses and begin to disappear on a large scale with only 15% solar dimming.

The disappearance and appearance of clouds has also been successfully simulated with the Dutch cloud model DALES. The model explains that the rising air is affected almost immediately when the partial eclipse begins . But everything changes on the sea. There the clouds are not affected during an eclipse because the sea water does not cool as quickly, so they remain even with darkness.

The researchers plan to continue their work using this new method to analyze data from past and future solar eclipses, with the goal of better understanding this interaction. Scientists now have a new tool to study the relationship between sunlight, clouds and climate , which will open a new chapter in geoengineering research.

News reference:

Victor JH Trees, Stephan R. de Roode, et.al. “Clouds dissipate quickly during solar eclipses as the land surface cools ,” Nature