For his dissertation, he deployed 25 instrumented gliders to gather data on lee waves, the newly discovered features forming downwind of mountains.
12.
In the Northern hemisphere, the generation of lee waves by mountains may locally cool the lower stratosphere and lead to the formation of PSCs.
13.
The strongest lee waves are produced when the lapse rate shows a stable layer above the obstruction, with an unstable layer above and below.
14.
The group plans particularly to study lee wave clouds, clouds of ice particles that form downwind of mountain peaks, in Scandinavia and the Urals.
15.
On 18 May 2005, Gordon Boettger flew 2061 km in his " Kestrel " in lee waves along the Sierra Nevada in the USA.
16.
In the early 1950s, Kuettner came to the United States and joined the Sierra Wave Project as scientific field director, investigating lee waves in California.
17.
All 113 passengers and 11 crew members died in the disaster, which was attributed to extreme clear air turbulence caused by lee waves downwind of the mountain.
18.
The rising air of the wave, which allows gliders to climb to great heights, can also result in high altitude upset in jet aircraft trying to maintain level cruising flight in lee waves.
19.
This predominantly occurs during the months of May, June, September and October when strong westerly winds flow at right angles to the ridge, and produce a large-scale standing wave ( Mountain Lee Wave ).
20.
Both lee waves and the rotor may be indicated by specific wave cloud formations if there is sufficient moisture in the atmosphere, and sufficient vertical displacement to cool the air to the dew point.
