I forgot to mention one thing (probably just as well, because I am not very sure of it). I seem to recall some notion that the more pole-ward circulations are largely driven by the Hadley cell, i.e. by heat input from the tropics, rather than the cold at the poles.
If we view the weather as a system for transferring heat from the tropics to the polar regions, we have heat input (insolation) and output (black body radiation). The amount of heat that is radiated out into space is dependent on the temperature at the surface of the earth (and at various levels of the atmosphere, but that gets really complicated). So there is more heat lost in the warmer tropics than at the cooler poles. However, the entire surface of the earth is in a fairly narrow temperature band somewhere around 200-300 degrees Kelvin; I think the difference in heat loss is much less than the difference in insolation. The point being that the heat _input_ in the tropics may be the determining factor driving these circulations, regardless of polar temperatures.
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branchandroot
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Date: 2022-05-15 09:30 pm (UTC)If we view the weather as a system for transferring heat from the tropics to the polar regions, we have heat input (insolation) and output (black body radiation). The amount of heat that is radiated out into space is dependent on the temperature at the surface of the earth (and at various levels of the atmosphere, but that gets really complicated). So there is more heat lost in the warmer tropics than at the cooler poles. However, the entire surface of the earth is in a fairly narrow temperature band somewhere around 200-300 degrees Kelvin; I think the difference in heat loss is much less than the difference in insolation. The point being that the heat _input_ in the tropics may be the determining factor driving these circulations, regardless of polar temperatures.