Why are there different vertical gradients of temperature in different layers of the atmosphere?

Question

The temperature of the troposphere decreases with altitude whereas it is opposite in the stratosphere and again fluctuates. Why is this so?

Answer 1

Hi Asked,

The troposphere gradient is governed by convection with resultant adiabatic cooling. There's not much circulation in the stratosphere, so it's governed by absorption of sunlight UV, I think mainly. And possibly some radiative cooling emission and capture. Higher than that, temperature ceases to be significant, the density is so low that the heat content is minor. -- Cheers, --- Mr. d.