Confinement and shedding

Large-scale atmospheric vortices like the polar vortex or the Asian monsoon anticyclone are known to confine compounds for several months in the corresponding regions of the stratosphere with many consequences on the transport and the resulting atmospheric composition, the chemical activity and radiative properties.

It was recently discovered that confinement over the same time scale occurs also in much smaller mesoscale anticyclonic vortices generated within the absorbing plumes of smoke or ash generated by large forest fires and some volcanic eruptions.

As a rule, the atmosphere dissipates rapidly all inertial structures and these vortices are all maintained by a sustained forcing. We will discuss the similarities and differences among those vortices, the smoke vortices being distinguished by their autonomy as they carry their own source of forcing when they travel around the globe.

We will discuss the phenomenon of isentropic vortex shedding which is a main mechanical dissipation factor and show that it behaves very similarly at all scales. In the vertical direction, the flux processor of the large vortices will be compared to and distinguished from the leaking process of the rising smoke vortices. Other processes associated with radiative relaxation of thermal anomalies play role both to maintain and dissipate.

Although the state of understanding of smoke vortices is still very incomplete, a discussion of their condition of formation, maintenance and stability will be offered based on observations and idealized numerical simulation.