Gravity Waves, Above the Indian Ocean
In this Terra image from 2003, a fingerprint-like feature occurs over a deck of marine stratocumulus clouds. The feature is the result of gravity waves. Similar to the ripples that occur when a pebble is thrown into a still pond, gravity waves sometimes appear when the relatively stable and stratified air masses associated with stratocumulus cloud layers are disturbed by a vertical trigger, such as
the underlying terrain, a thunderstorm updraft, or some other vertical wind shear. The stratocumulus cellular clouds that underlie the wave feature are associated with sinking air that is strongly cooled at the level of the cloud tops—such clouds are common over midlatitude oceans when the air is unperturbed by cyclonic or frontal activity.