ESS5
Prof. Jin-Yi Yu
Water Vapor (H2O)
qThe most abundant variable gas.
qWater vapor is supplied to the atmosphere by evaporation from the surface and is removed from the atmosphere by condensation (clouds and rains).
qThe concentration of water vapor is maximum near the surface and the tropics (~ 0.25% of the
atmosphere by volume) and decreases rapidly toward higher altitudes and latitude (~ 0% of the atmosphere).
qWater vapor is important to climate because it is a greenhouse gas that can absorb thermal energy
emitted by Earth, and can release “latent heat” to fuel weather phenomena.