:The term polar vortex/circumpolar whirl applies to both hemispheres.  There is no bias.     

 ==Proposed merger== 
 Since 10 months has gone by with no comment, I'll comment.  I support merger of the two articles.  The problem is, polar vortex is the more common term, so the polar cyclone article contents would need to be dumped into polar vortex, not vice versa.  A web search should verify this easy enough.