  Results from the laboratory experiments on the evolution of baroclinically
unstable flows generated in a rotating tank with topographic beta-effect are
presented. We study zonal jets of alternating direction which occur in these
flows. The primary system we model includes lighter fluid in the South and
heavier fluid in the North with resulting slow meridional circulation and fast
mean zonal motion. In a two-layer system the velocity shear between the layers
results in baroclinic instability which equilibrates with time and, due to
interaction with beta-effect generates zonal jets. This system is archetypal
for various geophysical systems including the general circulation and jet
streams in the Earths atmosphere, the Antarctic Circumpolar Current or the
areas in the vicinity of western boundary currents where baroclinic instability
and multiple zonal jets are observed. The gradient of the surface elevation and
the thickness of the upper layer are measured in the experiments using the
Altimetric Imaging Velocimetry and the Optical Thickness Velocimetry techniques
respectively. Barotropic and baroclinic velocity fields are then derived from
the measured quantities. The results demonstrate that the zonal jets are driven
by eddy forcing due to continuously created baroclinic perturbations. The flow
is baroclinic to a significant degree and the jets are surface intensified. The
meridional wavelength of the jets varies linearly with the baroclinic radius of
deformation and is also in a good agreement with a modified Rhines scale. This
suggests a linear dependence of the perturbation velocity in the equilibrated
baroclinically unstable flow on the beta-parameter.
