Shape of N polar cap explained, 3D structure and history from SHARAD data Options

[ngunn]

Article from Science Daily with link to Nature paper:
http://www.sciencedaily.com/releases/2010/...00526134150.htm

[schaffman]

A cold, dense air mass moving downslope (and southward) from the pole should create a katabatic wind that curves to the west (an easterly wind).
If these winds are responsible for eroding the troughs, then you'd expect the troughs to curve to the west as viewed by an observer at the pole looking south. Instead the troughs curve to the east.
In other words, the swirl pattern viewed from space should look like a like a counterclockwise spinning cyclone, not the clockwise pattern actually seen.
Tom