Clouds Like Honeycomb

NOAA-led team uses an innovative network approach to explain polygonal patterns in clouds

University of Colorado at Boulder

Polygons are widespread in nature: Drying mud may crack into many-sided blocks, and bees shape honeycomb into regular, six-sided cells. Hexagons also appear in broad sheets of clouds across parts of Earth’s oceans, and now a team of researchers has used a network approach to analyze why. Their work promises to help scientists to find more accurate descriptions of clouds in computer models of weather and climate change.

Large decks of stratocumulus clouds self-organize into honeycomb-like patterns. “These types of clouds cool the planet by reflecting solar radiation but their description in climate models is still rather crude”, said lead author Franziska Glassmeier. She found that she could use a relatively simple mathematical model to re-create the cloud patterns, which are shaped in nature by a complex interplay of physical processes.

The new paper, co-authored by NOAA scientist and CIRES Fellow Graham Feingold, is published today in the journal Proceedings of the National Academy of Sciences. The work was supported in part by the CIRES Innovative Research Program.

Since the first satellite images in the early 60s, scientists have recognized that stratocumulus clouds–carpet-like, low clouds often draped across large sections of subtropical oceans– look like imperfect honeycombs. Sometimes the cells are “closed,” with cloudy areas in the cells surrounded by cloud-free rings; and sometimes they are “open,” with cloud-free cells surrounded by cloudy rings. The pattern constantly changes as cells emerge, disappear, and re-arrange.