Mystery solved: Here is why clouds vanish during a solar eclipse

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Web Desk
A dove stands in an electric power pole during the annular solar eclipse in Brasilia, Brazil October 14. —Reuters
A dove stands in an electric power pole during the annular solar eclipse in Brasilia, Brazil October 14. —Reuters

When the Moon eclipses the Sun, casting a momentary shadow on our world, the spectacle is awe-inspiring and one surprising effect observed is the rapid dissipation of clouds, occurring when just 15% of the Sun is obscured by the Moon.

Victor Trees, leading a team from the Royal Netherlands Meteorological Institute and Delft University of Technology, focused on the disappearance of shallow cumulus clouds over land during a solar eclipse. 

This discovery, according to Trees, holds implications for climate engineering efforts. 

Blocking sunlight, a proposed solution to mitigate climate change may unintentionally reduce cloud cover. 

Since clouds reflect sunlight, they play a role in cooling the Earth.

Understanding cloud behaviour during an eclipse is challenging from the Earth's surface. The team tackled this by accounting for the Moon's shadow in satellite calculations of cloud top reflectivity. 

Surprisingly, cumulus clouds vanish when only 15% of the Sun is covered, reappearing once the eclipse concludes.

Simulations using cloud modelling software explained this phenomenon. When sunlight is blocked, the surface cools, diminishing warm air updrafts crucial for cumulus cloud formation. 

This effect occurs over land, impacting weather patterns, while the ocean remains unaffected.

Cumulus clouds, instrumental in weather patterns, may be influenced by climate geoengineering, prompting the need for further investigation. 

The study, shedding light on this intricate connection, has been published in Communications Earth & Environment.