Cloud "Communication"Wisps of clouds form a honeycomb-like structure (center) over the Peruvian coast (file photo).Such open-cell marine clouds "communicate" with each other so that they constantly oscillate, or rearrange themselves, in a synchronized pattern, according to a new study from the U.S. National Oceanic and Atmospheric Administration (NOAA).Inside the thick clouds of the cell walls, water droplets grow, then fall as rain, and the walls dissipate. The raindrops evaporate as they fall, cooling the air, which generates downward air currents.When the downdrafts hit the ocean surface, they flow outward and collide with each other and "force the air to move upward again" and "form new open cell walls at a different location," explained study co-author Hailong Wang, a cloud physicist at the Pacific Northwest National Laboratory in Richland, Washington.The new clouds eventually rain in unison, too, part of a reorganization cycle that can persist for days, according to the study.(Pictures: New Cloud Type Discovered?)—John Roach

Satellite image courtesy NASA