Experiments to study baroclinic waves penetrating into a stratified layer by a quasi-geostrophic potential vorticity equation

The upward penetration of the mid-latitude baroclinic waves has been well known to influence the air motion in the stratosphere. To study this in the laboratory, we present a new type of rotating fluid annulus experiment where a radial temperature difference is imposed on water near the flat bottom to produce a baroclinic wave in a lower layer and the water surface is heated to create a stratified upper layer. To test this model, we carried out experiments to study baroclinic waves penetrating into the stratified layer by a quasi-geostrophic potential vorticity equation in the atmospheric dynamics. The baroclinic waves produced in the lower fluid layer were observed to penetrate into the stratified upper layer. As expected from the equation, the vorticities of the flows for wavenumbers 3, 4 and 5 decayed exponentially with height and showed a weaker decay for lower wavenumbers.