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Have Australian rainfall and cloudiness increased due to the remote effects of Asian anthropogenic aerosols?

Rotstayn, Leon D; Cai, Wenju; Dix, Martin R; Feng, Yan; Ginoux, Paul; Herzog, Michael; Ito, Akinori; Penner, Joyce E; Roderick, Michael; Wang, Minghuai; Farquhar, Graham

Description

There is ample evidence that anthropogenic aerosols have important effects on climate in the Northern Hemisphere but little such evidence in the Southern Hemisphere. Observations of Australian rainfall and cloudiness since 1950 show increases over much of the continent. We show that including anthropogenic aerosol changes in 20th century simulations of a global climate model gives increasing rainfall and cloudiness over Australia during 1951-1996, whereas omitting this forcing gives decreasing...[Show more]

dc.contributor.authorRotstayn, Leon D
dc.contributor.authorCai, Wenju
dc.contributor.authorDix, Martin R
dc.contributor.authorFeng, Yan
dc.contributor.authorGinoux, Paul
dc.contributor.authorHerzog, Michael
dc.contributor.authorIto, Akinori
dc.contributor.authorPenner, Joyce E
dc.contributor.authorRoderick, Michael
dc.contributor.authorWang, Minghuai
dc.contributor.authorFarquhar, Graham
dc.date.accessioned2015-12-10T22:24:19Z
dc.identifier.issn0148-0227
dc.identifier.urihttp://hdl.handle.net/1885/53201
dc.description.abstractThere is ample evidence that anthropogenic aerosols have important effects on climate in the Northern Hemisphere but little such evidence in the Southern Hemisphere. Observations of Australian rainfall and cloudiness since 1950 show increases over much of the continent. We show that including anthropogenic aerosol changes in 20th century simulations of a global climate model gives increasing rainfall and cloudiness over Australia during 1951-1996, whereas omitting this forcing gives decreasing rainfall and cloudiness. The pattern of increasing rainfall when aerosols are included is strongest over northwestern Australia, in agreement with the observed trends. The strong impact of aerosols is primarily due to the massive Asian aerosol haze, as confirmed by a sensitivity test in which only Asian anthropogenic aerosols are included. The Asian haze alters the meridional temperature and pressure gradients over the tropical Indian Ocean, thereby increasing the tendency of monsoonal winds to flow toward Australia. Anthropogenic aerosols also make the simulated pattern of surface-temperature change in the tropical Pacific more like La Niña, since they induce a cooling of the surface waters in the extratropical North Pacific, which are then transported to the tropical eastern Pacific via the deep ocean. Transient climate model simulations forced only by increased greenhouse gases have generally not reproduced the observed rainfall increase over northwestern and central Australia. Our results suggest that a possible reason for this failure was the omission of forcing by Asian aerosols. Further research is essential to more accurately quantify the role of Asian aerosols in forcing Australian climate change.
dc.publisherAmerican Geophysical Union
dc.sourceJournal of Geophysical Research
dc.subjectKeywords: Atmospheric aerosols; Atmospheric pressure; Atmospheric temperature; Clouds; Greenhouse gases; Mathematical models; Pressure gradient; Rain; Transport properties; Wind; aerosol; anthropogenic source; climate change; climate effect; climate forcing; cloud
dc.titleHave Australian rainfall and cloudiness increased due to the remote effects of Asian anthropogenic aerosols?
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume112
dc.date.issued2007
local.identifier.absfor060705 - Plant Physiology
local.identifier.ariespublicationu9204316xPUB267
local.type.statusPublished Version
local.contributor.affiliationRotstayn, Leon D, CSIRO
local.contributor.affiliationCai, Wenju, CSIRO Division of Atmospheric Research
local.contributor.affiliationDix, Martin R, CSIRO
local.contributor.affiliationFarquhar, Graham, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationFeng, Yan, University of Michigan
local.contributor.affiliationGinoux, Paul, National Oceanic and Atmospheric Administration
local.contributor.affiliationHerzog, Michael, University of Michigan
local.contributor.affiliationIto, Akinori, University of Michigan
local.contributor.affiliationPenner, Joyce E, University of Michigan
local.contributor.affiliationRoderick, Michael, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationWang, Minghuai, University of Michigan
local.description.embargo2037-12-31
local.bibliographicCitation.startpageD09202 1
local.bibliographicCitation.lastpage28
local.identifier.doi10.1029/2006JD007712
dc.date.updated2015-12-09T09:16:17Z
local.identifier.scopusID2-s2.0-34347344079
CollectionsANU Research Publications

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