Martian Polar Vortex Dynamics

Strong wintertime polar vortices are observed in the Martian atmosphere. However, unlike the terrestrial stratospheric polar vortices, the Martian polar vortices are not a region of localized high potential vorticity (PV), but are in fact a region of low PV surrounded by an annulus of high PV. Although this annular PV structure would appear to be unstable, it is a persistence feature in observational-based analyses. Here we use atmospheric reanalyses, general circulation models, and idealized models of Mars to examine the dynamics and processes controlling the Martian polar vortex, and its annular PV structure.