White swirls on a blue background: what looks like rosettes or spoked wheels are a special form of clouds. Their radiation-like patterns can only be recognized well from space.
Clouds can take a wide variety of forms – from delicate veils and narrow ribbons to airy cotton balls to massive towers. Whoever looks up at the sky always sees other structures. However, some cloud shapes completely elude the viewer on the ground. This is the case, for example, with the so-called Actinoform clouds.
These special cloud systems mostly arise in the vicinity of low cluster layer clouds (stratocumuli) over the open ocean and sometimes reach an extension of 300 kilometers. Only when viewed from space through the eyes of a satellite are their geometric shapes easy to grasp.
The picture of these cloud rosettes was taken by NASA’s “Aqua” satellite at the end of January off the west coast of Australia – an unusual place of origin. “This scene is interesting because it takes place just north of the typical stratocumulus region west of Australia,” says Michael Garay of NASA’s Jet Propulsion Laboratory.
By the way, how these fascinating clouds are created is largely unknown. Researchers believe that aerosols may play a role in pattern formation. But so far from land, such particles can hardly be the dominant factor, as Garay explains.