Jets and submesoscale eddies in baroclinically unstable flows on the beta-plane: Experiments with altimetry

Results of the experiments on evolution of baroclinic flows in a rotating tank will be presented. The flows are generated by introducing lighter fluid in the “equatorial” region. This forcing creates slow meridional circulation and fast zonal flow. This system is archetypal for many oceanographic systems including the Antarctic Circumpolar current or the areas in the vicinity of western boundary currents. The flows contain multiple zonal jets, thin filaments and relatively small (submesoscale) eddies. Laboratory altimetry (Altimetric Imaging Velocimetry) is used to measure the slopes of the surface elevation and to obtain the velocity fields of the flow, not unlike a satellite altimetry used by oceanographers. The scales of the jets and eddies as well as spectral characteristics of the flows were measured. Unusual submesoscale eddies in the form of holes in the upper layer were observed. Their characteristics indicate that these eddies are strongly ageostrophic.