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The process of the gain and loss of solar heat sets up a general circulation pattern where the warm air parcels rises near the equator, flows away from the equator until the 30 degrees latitude, sinks near the poles, and the flows back to the equator.This process is called Hadley Circulation.
The air is parcels are not able to move beyond the 30 degrees latitude due to the conservation of angular momentum, especially the zonal velocity of the air must increase. The Coriolis effect is small.
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Note how the cold water would slowly move out from the center at the bottom (such as Blue #1, #2) and the eventually, the temperature of the outermost thermosisters would drop. The trend of the graph clearly decreases over time. There are minor "bumps" in the graph, which could be attributed to the rotation of the tank.
Then, we used the thermal wind equation for water, since water in the tank is an incompressible fluid:
where Ω = 0.1046 rad/sec, α = 207 * 10^-6^ K^-1, and dT/dr = 35.7 C/m. du/dz ended up to be 0.34 s^-1 from those values. The surface velocity was 0.054 m/s. The Hadley circulation is axisymmetric, especially in due to thermal wind balance with the radial temperature gradient.
(Costa……not sure what else to say from those numbers above…)
Atmospheric Examples
We have evidences the circulation from climatological plots of February:
(insert plots)
Eddy Circulation
Eddies are formed at high rotation rates and at middle to high latitudes. Coriolis forces have more effect, in this case. Due to the rotation, the Coriolis forces overpower pressures from temperature gradients, so the Hadley circulation breaks down. However, the heat must be transported from the tropics to the sub-tropics and the poles:
(Source: http://paoc.mit.edu/12307/gencirc/climatology_lab.pdf)
This can be explained by the conservation of angular momentum. When air parcels move to the higher latitudes, their zonal velocity must increase and their radius of their paths must decease to conserve angular momentum.
Tank Experiment of Eddy Circulation
The tank experiment of eddy circulation is similar to the set-up of Hadley circulation. Thermometers were placed a little differently than the set-up of Hadley circulation:
(Side-view of the tank and thermometers placement) (Christopoulos, 2014)
Another difference is that red and blue dye were used to observe the motion of cold and warm water in the tank. Blue dye was placed closer to the ice bucket while red dye was placed closer to the edge of the tank ("equator"). A series of images below show an evolution of the eddy circulation:
