Antarctic oscillation

===Positive===

===Positive===

In its positive phase, the westerly wind belt that drives the [[Antarctic Circumpolar Current]] intensifies and contracts towards [[Antarctica]].{{Cite journal|last1=Thompson|first1=David W. J.|last2=Solomon|first2=Susan|last3=Kushner|first3=Paul J.|last4=England|first4=Matthew H.|last5=Grise|first5=Kevin M.|last6=Karoly|first6=David J.|date=2011-10-23|title=Signatures of the Antarctic ozone hole in Southern Hemisphere surface climate change|journal=Nature Geoscience|language=En|volume=4|issue=11|pages=741–749|doi=10.1038/ngeo1296|bibcode=2011NatGe...4..741T|s2cid=40243634|issn=1752-0894|hdl=1959.4/unsworks_41958|hdl-access=free}} In winter, a positive phase increases rainfall (including [[East coast low]]s) in south-eastern Australia (above [[Victoria (Australia)|Victoria]]) due to higher onshore flows from the [[Pacific Ocean]], decreases rain in the south-west, and decreases snow in the [[Snowy Mountains|alpine]] areas. In spring and summer, a positive phase reduces the chance of extreme heat and increases humid onshore flows, therefore making spring and summer wetter than normal. A positive phase would usually occur more frequently with a [[La Niña]] event.[http://www.bom.gov.au/watl/about-weather-and-climate/australian-climate-influences.shtml?bookmark=sam Southern Annular Mode] Bureau of Meteorology, 12 June 2019

In its positive phase, the westerly wind belt that drives the [[Antarctic Circumpolar Current]] intensifies and contracts towards [[Antarctica]].{{Cite journal|last1=Thompson|first1=David W. J.|last2=Solomon|first2=Susan|last3=Kushner|first3=Paul J.|last4=England|first4=Matthew H.|last5=Grise|first5=Kevin M.|last6=Karoly|first6=David J.|date=2011-10-23|title=Signatures of the Antarctic ozone hole in Southern Hemisphere surface climate change|journal=Nature Geoscience|language=En|volume=4|issue=11|pages=741–749|doi=10.1038/ngeo1296|bibcode=2011NatGe...4..741T|s2cid=40243634|issn=1752-0894|hdl=1959.4/unsworks_41958|hdl-access=free}} In winter, a positive phase increases rainfall (including [[East coast low]]s) in south-eastern Australia (above eastern [[Victoria (Australia)|Victoria]]) due to greater onshore flow off the [[Tasman Sea]]; decreases rain in the south and south-west, and decreases snow in the [[Snowy Mountains|alpine]] areas. In spring and summer, a positive phase reduces the chance of extreme heat and increases humid onshore flows, therefore making spring and summer wetter than normal. A positive phase would usually occur more frequently with a [[La Niña]] event.[http://www.bom.gov.au/watl/about-weather-and-climate/australian-climate-influences.shtml?bookmark=sam Southern Annular Mode] Bureau of Meteorology, 12 June 2019

===Negative===

===Negative===