Vortex motions about vertical axes (corresponding to vertical vorticity) includes dust devils as well as includes much more common weaker vortex motions in both the stable (clear nights) and unstable (daytime surface heating) boundary layers.  At night, formation of these vertical vortices requires more significant winds, greater than a few m/s.  Because vortex motions are associated primarily with motions in the horizontal plane, they probably contribute little to the vertical transport.

The short video below shows a brief sequence of vertically oriented vortices associated with wind reversal induced by wave-like motion.  The vorticies appear as very transient dust devil-like circulations but are less organized because they coexist with other turbulent eddies of comparable strength.  The generation mechanism for these motions is not known although tilting of horizontal vorticity is thought to be the most likely cause.

The following video reveals vertical vorticity (horizontal rotation of the wind vector) that may be part of a solitary wave.  The vorticity is on the scale of the wave mode.  Each of the three cameras shows the same two vorticity events.

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