Gravity Waves in the Sky: Nature's Rippling Masterpiece

2. The Visual Spectacle of Wave Clouds

The visual expression of atmospheric gravity waves—that of wave clouds—is what most fascinates about them. Often referred to as undulatus or wave clouds, these clouds form an amazing show in the heavens that mimics ripples on a pond or the ridges of a sandy desert. When the oscillating air parcels approach the dew point, water vapour condenses into obvious cloud droplets and these clouds form. A range of cloud patterns can arise from this process, each with special visual attractiveness and features. There are several shapes for wave clouds, each providing a unique and amazing show. For example, at mid-levels of the atmosphere Altocumulus undulatus shows as parallel bands or rows of clouds. Often with a fish-scale look, these clouds can span large portions of the sky and provide a rippling image that seems to defy the ordinary randomness of cloud formation. Another kind, also referred to as Kelvin-Helmholtz clouds, arises from notable wind shear between two strata of air. With their unique curl patterns that can be both dramatic and fleeting, these clouds seem to be breaking ocean waves preserved in time. Wave clouds are a popular topic for photographers and sky watchers all over because of their aesthetic attractiveness. Often heightened by the movement of light and shadow, their consistent, recurring patterns produce a sense of rhythm in the heavens. These clouds can create amazing colours that span gentle pastels to strong, flaming tones during sunrise or sunset, therefore transforming the sky into a painting of vivid colours. For both casual viewers and weather aficionados, observing some wave cloud formations is an exciting experience due in part to their rarity and transitory character. Many have described seeing wave clouds as a mystical experience, a link to the great powers of nature forming our environment.