ESS101C
Prof. Jin-Yi Yu
Global Water Cycle
The
water cycle describes the fluxes of water between the various reservoirs
of the climate system.
(from The Blue Planet)
Water Reservoirs:
• Ocean
(97.5% of global water)
• Polar Ice Sheet (2.01%; 77.2% of fresh
water)
• Groundwater (0.58%; 22.1% of fresh
water)
• Atmosphere & surface streams, lakes (very
small
fraction)
Water Fluxes:
• Evaporation (from ocean+land to atmosphere)
• Precipitation (from atmosphere to ocean+land)
• Transpiration (land to atmosphere via
vegetation)
• Surface Runoff (land to ocean)