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1. Environmental Sciences: Towards a Sustainable Future Chapter 9 Water: Hydrologic Cycle and Human Use
2. The Water Cycle Exists to Purify Water There are three principal loops in the water cycle.
Human have managed to pollute or compromise the function of each loop.
We are running out of water in terms of quantity and quality.
Water conservation and stewardship are imperative actions.
3. Earth’s Water
4. Water Cycle Processes Evaporation: water molecules move from liquid to gaseous state; e.g. steam
Condensation: water molecules move from gaseous to liquid or frozen state; e.g. water droplets on cold beverage container
Purification: occurs as a result of evaporation and condensation; impurities are left behind
5. Condensation
6. Precipitation Adiabatic cooling: warm air rises, expands and cools
100% relative humidity + cooling = clouds
Increasing condensation = water droplets
7. Global Precipitation Global precipitation distribution depends on patterns of rising and falling air currents
Two main factors:
global convection currents
rain shadow effect
8. Rain Shadow Effect
9. The Water Cycle