A bit embarrassing but doesn’t click in my head. I have a BS in mechanical engineering and did pretty well in thermodynamics, aerodynamics, and heat transfer. I understand the pressure and temperature relationship of gases.
But when it comes to the weather, why does high atmospheric pressure cause hot temperatures? I understand the vice versa because gases expand (and raise to the top) when they are hot. So warm weather results in higher atmospheric pressure.
But why does high pressure cause hot temperatures? I would think hot air raises therefore the hot air should (almost always) be at the top of the atmosphere, leaving nice cool air for us at the bottom.
Also, it’s cooler the higher you go in altitude. But the air gets “thinner” as you go up.
P.S. I hate the heat.
In: Planetary Science
The PV=T you are familiar with is for closed systems and idealized scenarios.
The air at altitude isn’t less dense because its expanded by heat (although heated air will rise up and join it). Its less dense because it isnt being compressed. The air near the ground is being compressed by the air sitting on top of it.
You’ve also got the weather pressures reversed. Cold air masses are high pressure, hot air masses are low pressure.
Here’s a link that covers the subject as it relates to weather.
https://www.weather.gov/lmk/basic-fronts
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