Warming/Cooling the Earth
Warming
- Incoming radiation absorbed by surface (most important)
-
Air molecules in direct contact w/ surface warm via conduction
o Air near surface is very dense (a lot of molecules, draw  vs. z), so warm
molecules collide w/ other onesother molecules warmed
-
As air near surface warms, it becomes less dense than the air above it, so the warm
air rises and the cold air sinks (convection)
-
Rising air will cool as it ascends upwards, and expand. (gas law)
-
air may condense (releasing latent heat) and may form cloud droplets
-
earth emits longwave radiation, but some LW radiation is absorbed by atmosphere
(GH effect) and emitting back towards the surface
o Most CO2 and H2O is relatively close to surface, so GH effect deals with
atmosphere near surface
Cooling
- earth emits longwave radiation that escapes to space (most important)
-
only some LW radiation is absorbed by atmosphere (GH effect) and emitted back
towards the surface
-
Evaporation and evaporative cooling
o evaporative cooling: when rain evaporates it cools the surrounding air
o wind increases evaporationcools