GRAVITY WAVES ABOVE HURRICANE MATTHEW: Powerful Hurricane Matthew is scouring the islands of the Caribbean with 145 mph winds.  Orbiting high above the tempest in the darkness of space, the NOAA/NASA Suomi NPP satellite has observed the storm's ripple effect on the upper atmosphere:

These ripples are called "gravity waves"--essentially, waves of pressure and temperature excited by the upward motion of air from the storm below. Gravity does not vary inside these waves; instead, they get their name from the fact that gravity acts as a vertical restoring force that tries to restore equilibrium to up-and-down moving air. Similar patterns have been observed above powerful thunderstorms.
Matthew's gravity waves are visible from the ground as well.  Frankie Lucena of Cabo Rojo, Puerto Rico, captured them in his recent snapshots of sprites above the hurricane:

"Steven Miller of Colorado State University was kind enough to prepare these images for me to confirm that my sprite photo did contain gravity waves," says Lucena. "My location in southwestern Puerto Rico is noted in the satellite image above. By pointing my camera at the lightning, I also caught the waves."
Left to themselves, gravity waves would be invisible to the human eye. We see them, however, because they impress their patterns upon a luminous phenomenon called "airglow." Learn more about that in the next article, Amazing Airglow over Easter Island.

http://spaceweather.com/