And where did that rising heated air come from?

The sun heats the ground. The ground heats the air. The air expands
and goes up. Cooler air comes in from the outside of the desert, not
from above me.

Sure, there are some downdrafts, but the net is up.

Jose
--
Money: What you need when you run out of brains.
for Email, make the obvious change in the address.