Hydrological Cycle
¥85% of water vapor in atmosphere
evaporates from oceans.
¥About 40% of precipitation that falls
over land is runoff, and the other 60% is
transpired/evaporated.
¥Water vapor molecules reside in
atmosphere for about one
week on average
Ahrens Fig. 4.1
85%
15%
40%
60%
Ultimate source of all fresh water