Monday, August 16, 2010

NOAA scientists uncover oscillating patterns in clouds

NOAA: A new NOAA study has found that rain clouds form synchronous patterns in which individual clouds in a large cloud field respond to signals from other clouds, much like chirping crickets or flashing fireflies on a summer night. The study, published online today in the journal Nature also has significant implications for our understanding of climate change research.

This research, led by Graham Feingold of NOAA’s Earth System Research Laboratory in Boulder, Colo., shows for the first time that interactions between certain types of neighboring clouds can result in synchronized rain patterns within a large cloud system.

“Clouds organize in distinct patterns that are fingerprints of myriad physical processes,” Feingold explained. “Precipitation can generate fascinating honeycomb-like patterns that are clearly visible from satellites. Cloud fields organize in such a way that their components ‘communicate’ with one another and produce regular, periodic rainfall events.”

While the discovery of synchronized behavior in clouds is one of many recent findings on self-organization in nature, the study also examines how suspended particles, or aerosols, in the atmosphere can influence these patterns and be a factor in climate change.

…“Once precipitation ensues and an open structure has formed, it is difficult to revert the cloud field to a closed-cell, or overcast state,” Feingold said. “Rain keeps the oscillating, open honeycomb pattern in motion, which allows more sun to reach Earth’s surface.”

The scientists say that their findings point to a significant influence of particulate matter, or aerosols, on the large-scale structure of clouds and therefore on climate change. Scientists have long known that aerosols can influence local rain formation and block solar energy from reaching the Earth’s surface—for an overall surface cooling effect.

…“Our work also suggests that we should expand our thinking about interactions between aerosols and clouds,” Feingold said. “Integrating our current focus on fundamental physical processes with broader studies on system dynamics could give us a more complete understanding of climate change.”

Satellite image above Peru shows self-organizing honeycomb cloud pattern. From NASA

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