January 10, 2024

What’s That Cloud Look Like?

PNNL scientists use computer analysis to help explain the evolving shapes of clouds


PNNL researchers have found that as the shape of a cloud evolves, it demonstrates predictable patterns.

(Illustration by Shannon Colson | Pacific Northwest National Laboratory)

You may not be able to tell a book by its cover, but you probably can tell a cloud by its shape.

Researchers at Pacific Northwest National Laboratory (PNNL) have found that as the shape of a cloud evolves, it demonstrates predictable patterns. Using computer simulations, PNNL researchers determined that as clouds change shape, their edges become more jagged, but their overall shape does not change much. The research shows clouds with more jagged edges are more likely to split into multiple entities.

Moreover, the jaggedness of a cloud edge influences the growth and decay of the cloud, according to the study published in Geophysical Research Letters. The findings highlight the importance of cloud edge irregularity for the shape-shifting evolution of clouds.

“Clouds play a crucial role in regulating Earth's energy balance,” said Jingyi Chen, a PNNL Earth scientist and the study’s lead author. “The study findings could improve the accuracy in simulating cloud behavior, which could improve forecasting of weather and climate patterns.”

Researchers grappled with the fact that clouds are one of the most challenging components of climate models to simulate accurately, Chen said.

“Understanding how cloud shape affects cloud evolution and interactions with the surrounding atmosphere can lead to more realistic representations of clouds in climate models,” said Chen. “This, in turn, can lead to improved climate predictions and assessments of climate change impacts.”

Also, as a cloud evolved, it was more likely to split than to merge with other clouds. Also, perimeter growth favors cloud splitting over merging.

The findings could have an impact on analysis of broader weather conditions, Chen said.

“Climate researchers may consider extending their analysis to include various weather conditions such as studying how cloud shape evolution varies in different geographical settings, such as mountainous regions and urban areas, where local topography and human influences can impact cloud behavior differently,” she said.

“Clouds are a critical component of Earth’s climate system,” Chen said. “Changes in cloud properties can have significant feedback effects on climate. Understanding how cloud shape influences cloud properties and behavior can contribute to a better understanding of climate feedback, which are crucial for climate sensitivity assessments.”

Other PNNL researchers contributing to the research included Samson Hagos, Heng Xiao, Jerome Fast, Zhe Feng, and Adam Varble.

This study was supported by the U.S. Department of Energy, Office of Science, Biological and Environmental Research program as part of the Atmospheric Systems Research program.

Published: January 10, 2024

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