Lecture6_Water budget_biomes


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Unformatted text preview: e for human use. ► If we look at a what things do we need to take into account? Domestic use Commercial use Power plants Industrial use Irrigation Fish and wildlife habitat Navigation Recreation and waste removal Water Budget Water Budget ► Knowing the amount available for the various uses important. ► Measuring precipitation and determining evapotranspiration allow us to predict average river flow. ► The water budget help us determine why river flow are so much greater in humid regions than arid regions. The Global Water Budget estimates global averages rates of The evaporation, condensation, precipitation, and runoff. In the news In the news ► Earthquake in Indonesia http://www.msnbc.msn.com/id/33085687/ns/world_ne ► Tsunami in South Pacific http://www.msnbc.msn.com/id/33075304/ns/world_ne Water Budget Water Budget Is the water budget the same throughout the world? ► No, Each process of the water budget varies by location and the amount of water available. How does it work? ► Excess water evaporated into the atmosphere over the oceans in carried by wind over land areas, where its condenses into clouds and fall as precipitation. ► About 2/3 of the water that falls on land areas evaporates there, and the remaining 1/3 drains into rivers, which return to the sea as runoff. Water Budget Water Budget ► The water budget does not show variability of water from place to place and season to season. ► Evaporation from the sea depends on the insolation available to heat water. ► Precipitation and evaporation occur both land and ocean but not equal amounts. ► There are place that evaporation occurs more. ► More evaporation than precipitation occurs over the oceans. Evapotranspiration Evapotranspiration ► Evapotranspiration: Sum of evaporation and transpiration ► It varies by Seasonal variation ► Low in winter ► High in summer ► In the winter, when water uses is low, precipitation exceeds evapotranspiration. ► The surplus water either runs off or becomes stored as groundwater. ► In Springtime, plants develop leaves and water use rises rapidly, so that by early summer evapontranspiration exceeds precipitation. ► During the Summer, the excess water demand is met by the water stored in the soil, but by late summer, soil moisture is exhausted and water use is limited. ► In Autumn, evapontranspiration falls with the temperature and once again precipitation exceeds it. Evapotranspiration Evapotranspiration ► When we focused on local water budget, we recognize the importance role of plants in removing water from the soil. ► Where we have areas of high vegetation areas like Rainforest biomes, much of the conversion of water from liquid to vapor takes in the leaves. ► Water budget vary tremendously from one climate to another. ► Humid climates precipitation almost always meets demand. ► In semiarid and arid climates, the demand for water considerably exceeds precipitation. Water Availability Water Availability Water • Why is water so important? – Availability of water – Modifications of streams-dams – Water quality – Agricultural runoff into streams – Industrial pollution – Oil spills – Surf...
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This note was uploaded on 09/18/2013 for the course GEOG 100 taught by Professor Staff during the Fall '08 term at Maryland.

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