install theme

Sharp Line in the Clouds

[Credit: NASA image by Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response.]

"Dry air surging off the western coast of Africa ran into a wall of moist air over the Atlantic, creating a distinctive line in a marine cloud layer. Fast-moving, cool air masses often sweep from east to west across North Africa in the winter, sending surges of dry air over the Atlantic Ocean. When this dry air encounters moister and more stable air masses over the water, the clash can yield distinctive and beautiful patterns in the clouds.

On February 18, 2013, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this view of a thin layer of marine stratocumulus clouds off the coast of western Africa.

The air mass moving west pushed a wave of cool, dry air ahead of it, much like the bow wave of water that moves ahead of a boat in calm water. When that wave of air met the mass of moist air over the ocean, it pushed the moist air up. As that air rose, it cooled at the peak of the wave, forming a linear wave cloud. As the wave propagated forward, it rose to a slightly lower peak, and so on and so forth, until it eventually dissipated. The series of clouds that formed at the high-altitude peaks produced the rippling pattern seen in the clouds. This type of atmospheric disturbance is known as an undular bore. The air to the east of the bore is almost completely cloud-free because dry air would have eroded any clouds in that area.”

38 notes
comments powered by Disqus

38 notes


, #IOTD #NASA #Image of the Day #earth #Terra-MODIS
  1. tmblrbookmarks reblogged this from thescienceofreality
  2. priestsandpoliticians reblogged this from thescienceofreality
  3. averageanybody reblogged this from thescienceofreality
  4. heartoftardis reblogged this from thescienceofreality
  5. derpaderper reblogged this from thescienceofreality
  6. fireyourowncannons reblogged this from thescienceofreality
  7. girl-of-the-science reblogged this from thescienceofreality
  8. this-is-somestuff reblogged this from thescienceofreality
  9. etheleato reblogged this from thescienceofreality
  10. blackquilling reblogged this from thescienceofreality
  11. upping-the-ante reblogged this from thescienceofreality
  12. thescienceofreality posted this
^