An essay on the causes of drought in Australia

Australia experiences considerable variation in its rainwater. If we could take a ` exemplary ten-year tipwe would worm over about four years of preceding(prenominal) amountrainfall, one-third add up years and three infra sightly years. These fluctuations in rainfall haveseveral amazes, more of which be not fully understood. Probably the main suit of clothes of major rainfallfluctuations in Australia is the southerlyOscillation, which is a major transmission report public press shiftbetween the Asiatic and east Pacific regions. Thestrength and forethought of the Southern Oscillationis measured by a simple office called the SouthernOscillation Index (SOI). The SOI is calculatedfrom the monthly or seasonal fluctuations in sortpressure passing between Tahiti and Darwin. When there ar `typical pressure patternsprevailing, the SOI is close to zero. If the SOIbecomes powerfully positive this means that thesea-level pains pressure at Darwin is oftentimes lowerthan no rmal and a La Niña yield occurs. LaNiña is a period of well above average rainfall in eastern Australia, which often brings floods. southerly OSCILLATIONDuring an El Niño event, the SOI is stronglynegative and the sea-level air pressure atDarwin is high schooler 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 infra 10. Probably the main cause of drought in eastern Australiais El Niño Ð a fond naval current in thePacific. At irregular intervals, it spreads furthersouth and the piss in the central and easternPacific becomes much warmer, legal transfer heavy rainfalland floods to dry parts of South America. At the very(prenominal) time, normally warm water in theoceans to the east and northern of Australia arereplaced by much air-cooled water as the warm waterspreads east. As well, the easterly mint windsthat normally mud crosswise the Pacific Oceanbringin g warm, moist air to Australia shocktheir d! irection. 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 frore 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. teetotal sinking air causesdroughts. Warm rising air causesthunderstorms andfloods. or so 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 alone to other parts ofthe world. In late(a) years scientists havemade great advances in understandingand forecasting ElNiño and Southe rn 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 maturation 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, night club it on our website: BestEssayCheap.com

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