Cycle of water

Four sides that make up the cycle
Precipitation (rain, snow, dew, frost)
Runoff (river, groundwater); net water transport in the sea
Evaporation (including transpiration by plants)
Water vapor transport in the atmosphere
Expression of flow quantities
Mass passing per unit time (mass flux) [SI unit: kg / s]
Volume passing per unit time (assuming density 1 g/cm^3) [m^3 / s]
Annual mean discharge of Mekong river at Chiang Saen: 2500 m^3 /s
Mass passing per unit time per unit area (mass flux density)
 [SI unit: kg /(m^2 s)]
Volume passing per unit time per unit area (assuming density) [m / s]
Global mean precipitation: approx. 1000 mm / year
Mean residence time (or, turn-over time)
Existing mass / exchanged mass per unit time
Residence time of water vapor in atmosphere: approx. 9 days
Residence time of each molecule may be longer or shorter than it.