An essay on the causes of drought in Australia

Australia experiences considerable variation in its rainwater. If we could take a `distinctive ten-year tipwe would reverse over about four years of preceding(prenominal) amountrainfall, terce medium years and three infra come years. These fluctuations in rainfall haveseveral amazes, legion(predicate) of which be not fully understood. Probably the main apparent movement of major rainfallfluctuations in Australia is the southerlyOscillation, which is a major transmission aura public press shiftbetween the Asiatic and east Pacific regions. Thestrength and concern of the Southern Oscillationis measured by a simple list called the SouthernOscillation Index (SOI). The SOI is calculatedfrom the monthly or seasonal fluctuations in sortpressure deflexion between Tahiti and Darwin. When there ar `typical pressure patternsprevailing, the SOI is close to zero. If the SOIbecomes strongly positive this means that thesea-level mental strain pressure at Darwin is more than lowerthan normal and a La Niña font occurs. LaNiña is a period of well above average rainfall in east Australia, which often brings floods. southerly OSCILLATIONDuring an El Niño event, the SOI is stronglynegative and the sea-level air pressure atDarwin is high gearer than at Tahiti. An average yearoccurs when the SOI is between 10 and +10. ALa Niña event occurs when the SOI is above +10;an El Niño event occurs when it is on a lower floor 10. Probably the main cause of drouth in eastern Australiais El Niño Ð a fond marine current in thePacific. At irregular intervals, it spreads furthersouth and the water in the central and easternPacific becomes much warmer, legal transfer heavy rainfalland floods to dried-out parts of South America. At the very(prenominal) time, normally warm water in theoceans to the east and northern of Australia arereplaced by much cool water as the warm waterspreads east. As well, the easterly batch windsthat normally mar crosswise the Pac ific Oceanbringing warm, moist air to Austra! lia shocktheir direction. There is an accompanying reversalof air pressure across the Pacific, resulting instrong high pressure systems building up overWeather conditions in (a) a typical year, and (b) an El Niño year wintry deep waterEl NiñoTypicalOcean Cold upwellingceases. Warm surface currents reverse. AustraliaAustraliaTrade winds reverse direction.

AtmosphereAtmosphereSouthAmericaSouthAmericaOceanWarm surface waterStrong surface currentsUpwelling of colddeep waterTrade winds blow towards Australia. Warm come up aircauses thunderstormsand floods. change sinking aircauses droughts. change sinking air causesdroughts. Warm rising air causesthunderstorms andfloods. approximately of Australia. The result isstable and drier air dominatingAustralia with below averagerainfall and often severedroughts. El Niño brings signifi-cant climatic change, not only toAustralia yet to other parts ofthe world. In late(a) years scientists havemade great advances in understandingand forecasting ElNiño and Southern Oscillationevents. The National ClimateCentre in Australia offers outlookson rainfall three monthsahead. These outlooks are proving to be of greatvalue to farmers and especially valuable for ecologicallysustainable growth in rural areas. hypertext transfer protocol://library.thinkquest.org/C003603/english/droughts/causesofdroughts.shtmlhttp://www.vasat.org/learning_resources/drought/html/m1l3/resources/coping_with_drought/1660.html If you want to get a full essay, pasture it on our website: BestEssayCheap.com

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