A Lagrangian based approach for determining dispersion properties in forced beta plane flows: a laboratory study.

Geophysical turbulence is strongly influenced by the effects of
the variation of the Coriolis parameter with latitude. When this
effect holds, in the cascade process energy is preferentially
transferred towards zonal modes. This mechanism leads to the
organization of elongated jet-like structures which are nearly stable
and dominate the dynamics acting as robust meridional transport
barriers. Rhines? theory for unforced and barotropic flows indicates
that unless dissipation or the limited size of the field domain
arrests the inverse cascade, the energy is transferred towards slowest
modes and accumulates in correspondence of the so called ?Rhines
scale? thus preventing the growth of vortices in the meridional
direction . In this work we analyze Lagrangian data obtained tracking
with image analysis styrene particles seedded in a rotating tank where
turbulence is generated by continuously forcing a thin layer of an
electrolyte solution using a superposition of magnetic and electric
fields. The variation of Coriolis parameter is simulated by the
parabolic profile of the free surface of the rotating fluid. The
obtained (O(10000)) trajectories are used to evaluate the FSLE and
analyze spatial anisotropy in the dispersal properties.