Gravity wave in Venus upper atmosphere
Soon after arrival to Venus orbit in July 2015, Japanese spacecraft Akatsuki (Planet-C or Venus Climate Orbiter) registered strange phenomena.
Image: JAXA
Images, captured in IR and UV spectra show giant atmospheric wave, stretched between poles across whole planet disk. It rests at 65 kilometers height in the clouds of sulphuric acid.
Image: Nature geoscience
Venus atmosphere is very active: it does complete turn around planet in 4 Earth days, much faster than planet's surface. This means that at 65 km height wind speed is about 100 meters/s, but the wave is stationary
Image: Novosti-kosmonavtiki
This feature stayed at place during all December 2015, then disappeared. The center of the wave stood exactly above highland area (or continent) Aphrodite Terra, region of Africa size.
In January 2017 Japanese scientists published in Nature an article with explanation of this phenomena: this is atmospheric gravity wave, tightly connected with mountains on the surface.
It is still unclear why this wave had disappeared after one month
Just to clarify - these are "gravity waves", not "gravitational waves".
They are 2 different phenomena.
Gravity waves - what your article discusses - have to do with atmospheric disruptions caused by a planet's gravity.
Gravitational waves are waves that ripple through the fabric of spacetime, particularly when 2 black holes collide.
Thank you! Corrected