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Droughts

By : The best group of all. Droughts. Definition. Drought : Is an extended period of months , years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. Causes.

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Droughts

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  1. By: Thebestgroup of all Droughts

  2. Definition • Drought: Isan extended period of months, years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation.

  3. Causes • Water vapor condenses only if air rises into the colder regions of the atmosphere. • When the air doesn’t rise, then no rain will form. • When there is high air pressure, air falls instead of rising. • With the air pressing down in a high pressure zone, no currents of water vapor are carried upward.

  4. Causes • As a result, no condensation occurs, and little rain falls to earth. In addition, high-pressure areas push clouds and air currents downward and away, resulting in sunny, cloudless weather. • Mountains can prevent wind from blowing moisture to needed regions. • Atmospheric conditions such as climate change, ocean temperatures, changes in the jet stream may help in the development of droughts.

  5. Ethiopia • A bad allocation of the resources, such as water, since Ethiopia is a land that sends water to all its neighbours thanks to its richness in lakes, it should have allocated the water from lakes to the north in order to use it for the crops since northern Ethiopia is a very dry area. • Over grazing and over use of the farming has damaged the soil which leads to water loss by run off since the soil doesn't absorb the water. 

  6. Effects • Farmers have to receive emergency agricultural assistance. However situation has got worse and they can’t even feed themselves. • Farmers lost their lands as they were production inefficient. • Animals are dying due to lack of water and feed after repeated failed harvests.  •  Most locals rely on food aid, in the present

  7. Effects • In 2003 12.6 millions were in need of food aid. In 2009, 14 million, 20%. • Overall, economy was severed. • Aid: $4.3 million to farmers • Tens of thousands of families are to be moved before the rains come

  8. Frequency of occurrence • Ethiopiaevery ten years • Per year el Niño and the Niña. (Australia and Indonesia)

  9. Predictability • The longevity of a drought depends mainly on: • air-sea interactions • soil moisture • land surface processes • topography • internal dynamics • changing weather systems around the world • High pressure • The two main parameters needed for a successful prediction of droughts are precipitation and temperature. • Atmospheric conditions depend in the variations of the tropical sea surface temperatures

  10. Bibliography • http://www.time.com/time/world/article/0,8599,1915544,00.html • http://www.fao.org/english/newsroom/news/2003/18548-en.html

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