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Given that air should rise near the equator and sink in the vicinity of the polar regions, in a non-rotating system one would expect the motion of fluid to be purely meridional i.e. towards the poles in the upper levels, and away from the poles and directed equatorially at the surface. However, the earth is a rotating system with the atmosphere in roughly solid-body rotation. Therefore, we must take this into consideration and do so by using the Coriolis parameter. Because the Coriolis deflection is weakest at the equator and considering that fluid at the equator orbits the globe where its radius is the greatest, its angular momentum is greater than at any other point on earth since the earth is a solid body. Therefore, by the conservation of angular momentum, we would expect that, to conserve momentum, a parcel of air from the equator attempting to move towards the pole would be deflected eastward in direction since its zonal velocity must increase. Therefore, at the upper levels, a westerly jet should form , being strongest as one heads away from the equator. For the sinking air later in its poleward journey, the opposite should be true; as it returns towards the equator, its weakening horizontal velocity due to the increase in radius should lead to surface easterly forming, strongest at the equator. This gives rise to the Intertropical Convergence Zone, where both Hadley cells converge. The rising motion here, coupled with the easterly winds (and the subtropical easterly jet, which, due to surface friction, is considerably weaker than other jets) leads to the development of tropical waves, and is an integral portion of cyclone forecasting.
When the Coriolis parameter is low, the fluid will be mainly laminar, and be governed by the physics of the Hadley cell. However, the entire globe cannot exist as a Hadley cell; proof of this can be sought within the Law of Conservation of Angular Momentum. Given that the radius of a parcel's orbit would be zero at the poles, utilizing solely this law would yield infinite winds aloft at those locations. Given that this is quite impossible, we are forced to rely on eddy heat transport, which "takes care of angular momentum" in other ways by breaking down polar heat transport into more localized vortices. This offers takes effect at latitudes in the 30-90º regime, where the Coriolis parameter is too great to maintain the laminar nature of the fluid, which results to in turbulence. Elsewhere towards the equator, the fluid is largely laminar, leading to Hadley cells becoming the main means of heat transport between 30ºN and 30ºS.
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Several key differences exist between the earth and our tank experiment; after all, one is a three dimensional rotating sphere comprised of solid, liquid, and gas, complete with pressure gradients amidst the fluid as well as several means of thermal heat fluxes. Meanwhile, the tank is a two-dimensional representation, and the incompressible nature of the fluid water leads to further behavioral differences.
At its root a large rotating cylinder about 0.6-0.7 meters in diameter and 0.25 meter tall , the acted as a representation of only one hemisphere. Towards the center of the tank, which one can envision "flattening" as a net against the hemispherical form of either the top of bottom half of the globe, a small bucket of ice was placed. The ice was contained in a metal cup with a low specific heat capacity, which then transferred the cooling effect through conduction to the water closest to the center. As such, a horizontal temperature gradient was instigated within the tank, thus allowing the periphery of the tank to become the relative warm "spot," with the fluid rising accordingly, while sinking towards the center of the tank. Between, as the warm fluid rose along the edges, it moved radially inwards, where it sank and expanded outwards towards the edges.
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