Ch 7 - 1. What are the lessons to be learned from the Aral...

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1. What are the lessons to be learned from the Aral Sea story? The diversion of water can be an environmental and economic disaster. Doing something without thinking through the consequences can be disastrous. The fishing industry dependent upon the Aral Sea has been destroyed; the health of residents in the area has been adversely impacted (increased cancer and infant mortality rates, increased respiratory irritation); the local climate has changed; many species have gone extinct. 2. Give examples of the infrastructure that has been fashioned to manage water resources. The infrastructure includes dams, reservoirs, aqueducts, canals, intake and outflow pipes, water and sewage treatment plants, water storage facilities, and the piping from and to homes and businesses. 3. What are the two processes that result in natural water purification? State the difference between them. Distinguish between green water and blue water. Water rises to the atmosphere through evaporation and returns to the Earth’s surface after condensation through precipitation. This process purifies water because only water evaporates. All impurities are left behind during the process of evaporation. After condensation of the evaporated water, only water is present. Water will remain clean as it returns to the Earth’s surface as long as it does not fall through an area with air pollution. Green water is “water in the soil and in organisms that eventually ends up as water vapor—the main source of water for natural ecosystems and rain-fed agriculture.” Blue water is “renewable surface water runoff and groundwater recharge—the focus of management and the main source of water for human withdrawals.” 4. Describe how a Hadley cell works, and explain how Earth’s rotation creates the trade winds. Hadley cell: “Dry air absorbs moisture as it descends” “Moist air releases moisture as it ascends” “Global convection currents occur because the sun heats the Earth most intensely over and near the equator, where rays of sunlight are almost perpendicular to Earth’s surface. As the air at the equator is heated, it expands, rises, and cools; condensation and precipitation occur.” “Rising air over the equator is just half of the convection current, however. The air must come down again, too. Pushed from beneath by more rising air, it literally ‘spills over’ to the north and south of the
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equator and descends over subtropical regions, resulting in subtropical deserts. . . .” The Earth’s rotation deflects the vertical and horizontal path created by the Hadley cell, thus creating trade winds. 5. Why do different regions receive different amounts of precipitation? Different amounts of precipitation in different regions
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This note was uploaded on 10/08/2008 for the course EMERITUS O 101 taught by Professor Richardtwright during the Spring '08 term at Gordon MA.

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Ch 7 - 1. What are the lessons to be learned from the Aral...

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