Gravity Waves
From New Scientist, 11 Oct:
The existing method of warning pilots of CAT, called Graphical Turbulence Guidance, relies on pilot reports and observations of the atmosphere, including lightning data, but is not particularly accurate. To improve on these predictions Williams and his colleagues decided to focus on the cause of the turbulence: the gravity waves generated at the boundary of fast-moving high-altidude jet streams with slower moving air. Their model uses wind speed measurements to predict where these boundaries lie, and so where the gravity waves are likely to be strongest.
After initially thinking they were talking about fluctuations in the space-time continuum I realised the reference was to fluid dynamics. Done a bit of googling and I can understand the idea of gravity waves initiated by terrain but I'm still not getting the idea of gravity waves induced by jetstreams. Anyone come across this?