Zonal Jets in Rotating Shallow Water Turbulence

Abstract

During the last three decades, the appearance of multiple zonal jets in planetary atmospheres and in the Earth’s oceans has widely studied. Evidences of this phenomenon were recovered in numerical simulations [1], laboratory experi-ments [2-4] and in field measurements of giant planets’ atmosphere [5]. Recent studies have revealed the presence of zonation also in the Earth’s oceans; in fact, zonal jets were recovered in the outputs of Oceanic General Circulation Models-GCMs [6] and from satellite altimetry observations [7]. In previous works [3-4], we have investigated the impact of several experimental parameters on jets organization both in decaying and forced regimes. This work shows new results in the context of continuously forced flows obtained performing experiments in a bigger domain. The experimental set-up consists of a rotating tank where the initial distribution of vorticity is generated via the Lorentz force in an electromagnetic cell and the latitudinal variation of the Coriolis parameter is simulated by the parabolic profile assumed by the free surface of the rotating fluid. The velocity fields were measured using an image analysis technique. The flow is characterized in terms of zonal and radial flow pattern, flow variability and jet scales.