Potential use for climate engineering or not?

Cumulus clouds over the ground almost instantly begin to disappear partial solar eclipse. Until recently, satellite measurements during the eclipse resulted in dark areas appearing on the cloud map, but researchers from TU Delft and KNMI were able to reconstruct the satellite measurements using a new method.

Results may have implications for proposed ideas climate engineering because disappearing clouds can partially counteract the cooling effect of artificial solar eclipses. The results were published in Connection Earth and environment.

Although the effects of solar eclipses have been studied for centuries, it is unknown exactly how strong clouds react to them. “From Earth you can count the clouds and watch them disappear, but this is only anecdotal evidence.– explains the candidate of technical sciences Victor Tris. “Even without a solar eclipse, clouds are constantly changing.And”.

Measuring solar eclipses from space

Satellites in geostationary orbit They can continuously measure many clouds simultaneously over large areas, including impassable terrain. During a solar eclipse, measurements were unreliable because satellite algorithms did not take into account the decrease in sunlight during solar eclipses. This resulted in large dark spots appearing on the cloud maps.

Researchers have now managed to reconstruct satellite measurements during solar eclipses by accurately calculating the percentage of the Sun hidden for each place and time on Earth. “Of course, most of the solar eclipse is a partial eclipse, in which there is still a lot of light outside. During this partial eclipse, the satellites receive enough reflected sunlight, after correcting for obscuration, to reliably measure clouds.“.

Cumulus clouds over Earth are very sensitive to solar eclipses

IN Cloud maps recovered from three solar eclipses In Africa, researchers saw that Cumulus clouds began to disappear en masse after just 15% solar eclipse.. Once the solar eclipse is over, the cumulus clouds will return. On days when there is no solar eclipse, this behavior of clouds is not observed.

The disappearance and appearance of clouds was also successfully simulated using the Dutch cloud model DALES.. The model explains that rising air is affected almost immediately when a partial eclipse begins. Over the sea, during a solar eclipse, clouds are not affected because sea water does not cool so quickly. See the image below for details.

Possible implications for climate engineering

They currently offer Strategies for artificially cooling the Earth. For example, place reflective solar sails in space or aerosols in the stratosphere. These concepts create a subtle and possibly variable solar eclipse. But according to Treece’s research, clouds begin to disappear en masse after a partial eclipse.

“It could be warning for climate control equipment. If we eclipse the sun with technological solutions in the future, this could affect the clouds. Fewer clouds may partially offset the desired effect of climate engineering, as clouds reflect sunlight and therefore help cool the Earth.“In addition, clouds determine local precipitation patterns. The high sensitivity of clouds to solar eclipses requires further research into the possible effects of artificial shading.

Link

Victor J. H. Treece et al. Clouds disperse quickly during solar eclipses as the earth’s surface cools, Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01213-0