File:Cloud streets in the Greenland, Norwegian, and Barents Seas (MODIS 2017-04-03).jpg

English: On March 28, 2017, the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured a stunning true-color image of cloud streets over the Greenland, Norwegian, and Barents Seas.

Greenland sits in the northwestern section of the image while Norway, Sweden, and Finland are located in the south. The Greenland Sea lies off the coast of Greenland and blends with the Norwegian Sea, which lies north and west of Norway. The Barents Sea sits to the northeast of Norway and north of Russia. Cloud streets, which are long, parallel bands of cumulus clouds, stretch roughly from north to south over each of these bodies of water.

Cloud streets are formed when cold air blows over relatively warmer waters. To transport the heat away from the sea surface, columns of heated air called thermals naturally rise through the atmosphere. The air masses rise until they hit a warmer air layer (temperature inversion), which acts like a lid. The rising thermals roll over when they hit this ‘lid’, and loop back on themselves, creating parallel cylinders of rotating air. On the upper edge of these cylinders of rising air, clouds form. Along the downward (descending air), skies are clear.