Circulation of the Venus upper mesosphere/lower thermosphere: Doppler wind measurements from 2001-2009 inferior conjunction, sub-millimeter CO absorption line observations

► The global circulation of the Venus upper atmosphere was measured over 2001-2009. ► Distinctly different types of global circulation transition over timescales as short as a day. ► Simple diurnal and zonal circulations typically account for only 50% of the observed circulation.