Lake Effects, Aral Sea and Great Lakes

The Aral Sea created an unusual pattern of wave clouds in the image above, captured by NASA’s Aqua satellite in March 2009. Wave clouds themselves aren’t especially rare, but they are usually formed when high topography (such as a mountain) or a strong updraft of air causes a disturbance in a cloud layer. Here, the shore of the Aral Sea is clearly creating the disturbance, which could be the result of a sudden uptick in wind speed as the air reaches the smooth surface of the lake, or by the shoreline which has steadily been growing higher than the water surface as the Aral Sea shrinks over time.

A more typical lake effect is seen in the image below of the Great Lakes region of North America, taken by the sea-viewing wide field-of-view sensor (SeaWiFS) aboard GeoEye’s SeaStar satellite in December 2000. As cold air flows northwest across the relatively warm Lakes Nipigon (top left), Superior, and Michigan, the warm, moist air rises and mixes with with the cold, dry wind forming a stratocumulus cloud layer. As the process continues, the water droplets in the cloud layer may freeze and grow into snowflakes, sometimes creating massive snowstorms.

Images: 1) Jeff Schmaltz/NASA. 2) GeoEye/SeaWiFS.