|
|
|
|
|
|
Solar
energy incident on the Earth |
|
= total amount of solar
energy can be absorbed by Earth |
|
= (Solar constant) x (Shadow Area) |
|
= S x p R2Earth |
|
|
|
|
|
|
Distance
from the Sun |
|
Albedo |
|
Greenhouse effect |
|
|
|
|
|
|
On Venus
è 510°K (very large!!) |
|
On
Earth è 33°K |
|
On
Mars è 6°K (very small) |
|
|
|
|
Venus is
too close to the Sun |
|
Venus
temperature is very high |
|
Very
difficult for Venus’s atmosphere to get saturated in water vapor |
|
Evaporation keep on bringing water vapor into Venus’s
atmosphere |
|
Greenhouse effect is very large |
|
A “run
away” greenhouse happened on Venus |
|
Water
vapor is dissociated into hydrogen and oxygen |
|
Hydrogen
then escaped to space and oxygen reacted with carbon to form carbon dioxide |
|
No water
left on Venus (and no more chemical weathering) |
|
|
|
|
Mars is
too small in size |
|
Mars had no large internal heat |
|
Mars lost all the internal heat quickly |
|
No tectonic activity on Mars |
|
Carbon can not be injected back to the
atmosphere |
|
Little greenhouse effect |
|
A very cold Mars!! |
|
|
|
|
|
|
|
|
|
|
|
The larger the solar zenith angle, the weaker
the insolation, because the same amount of sunlight has to be spread over a
larger area. |
|
|
|
|
Polarward heat flux is needed to transport
radiation energy from the tropics to higher latitudes. |
|
|
|
|