During a solar eclipse, the Moon’s shadow causes a brief darkening on Earth, leading to the unexpected rapid clearing of clouds when the Sun is only 15% covered by the Moon. Victor Trees and his team from the Royal Netherlands Meteorological Institute and Delft University of Technology studied the phenomenon, focusing on the vanishing of shallow cumulus clouds over land during such events.
Trees suggest these findings are crucial for climate engineering strategies aimed at sunlight reduction to combat climate change, highlighting potential unintended effects on cloud cover. Clouds, which reflect sunlight, help cool the planet. The team’s approach involved adjusting satellite measurements for the Moon’s shadow to analyze cloud top reflectivity during eclipses.
They discovered cumulus clouds disappear with minimal solar coverage, a change not observed over oceans. This behaviour, explained by simulations, is due to reduced surface heating and a subsequent decrease in warm air updrafts necessary for cloud formation. The implications for weather patterns and climate geoengineering underscore the importance of this research, published in Communications Earth & Environment.
