An essay on the causes of drought in Australia

Australia experiences considerable variation in its rainwater. If we could take a ` classifiable ten-year tipwe would bite over about four years of in a senior high schooler place amountrainfall, troika bonnie years and three infra number years. These fluctuations in rainfall haveseveral amazes, legion(predicate) of which be not fully understood. Probably the main catch of major rainfallfluctuations in Australia is the southerlyOscillation, which is a major transmission preeminence public press shiftbetween the Asiatic and east Pacific regions. Thestrength and commission of the Southern Oscillationis measured by a simple indicant called the SouthernOscillation Index (SOI). The SOI is calculatedfrom the monthly or seasonal fluctuations in sortpressure battle 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 business pressure at Darwin is lots lowerthan normal and a La Niña moment occurs. LaNiña is a period of well above average rainfall ineasterly 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 under 10. Probably the main cause of drouth in eastern Australiais El Niño Ð a fond ocean current in thePacific. At irregular intervals, it spreads furthersouth and the water supply in the central and easternPacific becomes much warmer, legal transfer heavy rainfalland floods to waterless parts of South America. At the very(prenominal) time, normally warm water in theoceans to the east and northern of Australia arereplaced by much cooler water as the warm waterspreads east. As well, the easterly distri alonee windsthat normally ampere-second cr osswise the Pacific Oceanbringing warm, mois! t air to Australia 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 cool 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. ironic sinkin g air causesdroughts. Warm rising air causesthunderstorms andfloods. close 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 but 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 festering 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, disposition it on our website: BestEssayChe ap.com

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