02/19/10

During my latest stay in Antarctica I saw plenty of lennies, and experienced lots of mountain wave action (in a DeHavilland Twin Otter!). I also witnessed a most remarkable phenomenon coming back from work one afternoon:

That day we had seen medium and high altitude lennies throughout most of the survey area. We were flying at approximately 1500 feet AGL when I noticed low level fog. It must have been between ground level and at most 75 feet AGL. Soon, the fog started developing into organised patterns reminiscent of wave clouds. Surface winds were between 20 and 40 knots. Usually with that much wind one doesn't see a lot of fog. This went on for a distance of maybe 150Km, alternating between various types of lennies. Quite difficult to describe, so better see the pictures below.

There was evidence of wave early into the flight.	Large lenticular as could be seen near the mountains.	Near the mountain, the view of the ground was clear.
At first there was no fog.	Then, suspicious fog started to appear.	One could definitely see wavy pattern in it.
One could definitely see wavy pattern in it.	One could definitely see wavy pattern in it.	At this point, a better established wave was evident.
At this point, a better established wave was evident.	It is easy to see how thin the layer was. It was hugging the ground, and couldn’t have been any higher than 75ft.	The pattern started becoming more dense.
Perhaps a bit taller than before.	Perhaps a bit taller than before.	The patterns were perfectly aligned.
Typical lenticulars, but in small scale, and very close to the ground.	Textbook wave.	Textbook wave.