Mesoscale circulations near the tropopause

Jim Holton was keenly interested in the role of mesoscale circulations in stratospheric-tropospheric exchange, particularly deep convection. This talk will begin with a brief review of work conducted by Jim, myself and others on cross-tropopause exchange of momentum and chemical tracers in deep convective clouds, including the role of convectively generated gravity-waves in the QBO and the potential for rapid transport of chemical tracers from the boundary layer to the lower stratosphere. The focus will then shift to new work on the mesoscale circulations associated with sub-visible tropical cirrus and their role in heating the upper troposphere.