This shows thunderstorm clouds in cross-section. The new younger cloud in the middle hasn't started to spread out yet, so doesn't have the large thin glaciated anvil at the top. The tropopause is the boundary between the red and white (in the tropics at about 15 km). The stratosphere is white because of the sulfate aerosol layer from the eruption of Mt. Pinatubo. This layer cooled the earth for several years after the eruption (1991 - 1993). The reason the layer persists in the stratosphere for several years is because clouds don't go into the stratosphere, so the little aerosol particles don't get rained out. (Would come down within a week as acid rain if near the surface.) Venus has sulfate aerosol clouds all the time because there is no rain on Venus (too hot and dry).

These two tropical images give the impression of what scientists call "convective instability" - the continual overturning (boiling) of the tropical atmosphere caused by surface solar heating and cooling aloft by greenhouse gases. Convective instability causes rain. A big question in climate science is how much more rain there will be as we increase greenhouse gases and increase cooling rates aloft (i.e. production of heavy air), and what the net effect on soil moisture will be.