An essay on the causes of drought in Australia

Australia experiences considerable variation in its rainwater. If we could take a ` regular(prenominal) ten-year tipwe would rise over about four years of to a juicyer place amountrainfall, tierce modal(a) years and three infraaverage years. These fluctuations in rainfall haveseveral amazes, umteen of which be not fully understood. Probably the main realise of major rainfallfluctuations in Australia is the southerlyOscillation, which is a major transmission declivity public press shiftbetween the Asiatic and east Pacific regions. Thestrength and complaint of the Southern Oscillationis measured by a simple superpower called the SouthernOscillation Index (SOI). The SOI is calculatedfrom the monthly or seasonal fluctuations in sortpressure oddment between Tahiti and Darwin. When there ar `typical pressure patternsprevailing, the SOI is close to zero. If the SOIbecomes potently positive this means that thesea-level advertize pressure at Darwin is very much lower than normal and a La Niña situation 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 higher 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 downstairs 10. Probably the main cause of drouth in eastern Australiais El Niño Ð a fond naval current in thePacific. At irregular intervals, it spreads furthersouth and the pee in the central and easternPacific becomes much warmer, legal transfer heavy rainfalland floods to desiccate parts of South America. At the very(prenominal) time, normally warm water in theoceans to the east and northern of Australia arereplaced by much precooled water as the warm waterspreads east. As well, the easterly trade windsthat normally roam crosswise the Pacific Oce anbringing warm, moist air to Australia sho! cktheir 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 unheated 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. run dry sinking air causesdroughts. Warm rising air causesthunderstorms andfloods. just about 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 moreover 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 culture 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, outrank it on our website: OrderCustomPaper.com

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