The bottom-up mechanism for total solar irradiance (TSI). Main features of the bottom-up mechanism. Based on Gray et al. () and Meehl et al. (); see these references and text for more details. This figure, as well as the following figures, presents a pole-to-pole latitudinal cut showing the layer structure from the oceans to atmospheric layers covering the altitudes from the troposphere to the lower thermosphere. The winter and summer poles and the equator have been marked at the top.