|Tropical Low Clouds
Tropical low clouds do little to change OLR since the tropical atmosphere is already optically thick. Also, they do not significantly alter greatly surface downwelling longwave radiation.
Thus they have little longwave impact at the surface or TOA. However, they do reflect sunlight. Since the longwave and shortwave impact of tropical low clouds do not offset each other, they play a particularly important role in cooling the planet.
|Midlatitude and Polar Low Clouds
Midlatitude and polar low clouds lead to surface warming.
They lead to significantly more downwelling longwave radiation hitting the surface and thus warm the surface. They also reduce OLR and reflect sunlight. Thus, they have both a global warming (longwave) and cooling (solar) effect.
If global warming were to lead
to more low clouds in the tropics how would this feedback on the Earth
system. Would an increase in low clouds in midlatitudes have as strong
of an impact?