How Extreme Apparitions of the Volcanic and Anthropogenic South East
Asian Aerosol Plume caused the Millennium Drought in South Eastern
Australian. First Attribution and Mechanism using data from the Last
Millennium Ensemble, Large Ensemble, MERRA-2 Reanalysis, four Satellites
and the Global Volcanism Program.
Abstract
The Last Millennium Ensemble, Large Ensemble, MERRA-2, four satellite
data sets and the Global Volcanism Program database all show
independently that drought in south eastern Australia (SEAus) is created
by apparitions of the natural and anthropogenic aerosol plume over south
east Asia which simultaneously create ENSO and IOD events. From 1997 to
2008 SEAus endured an exceptionally severe drought - the Millennium
Drought. The River Murray, the major waterway in the region, experienced
inflows at record low levels in 2006-07 which were more than 40% below
the previous low. As the literature, Inter Governmental Panel on Climate
Change (IPCC) and the USA Climate Change Science Program suggest that
aerosols can affect the large-scale atmospheric circulation and
hydrologic cycle I examine the relationship between aerosols and
Australian droughts. The global aerosol coverage is highly inhomogeneous
and variable at daily, monthly, annual and decadal scales. I show that
the aerosol optical depth (AOD) and aerosol index (AI) of the South East
Asian Plume (SEAP) and the volume of aerosols ejected by volcanoes
(tephra) in south east Asia correlate with drought in Australia and
conclude that the SEAP causes drought in Australia by Aerosol Regional
Dimming (ARD), which, by altering the surface radiation budget under the
plume and warming the upper atmosphere, forces the regional Inter
Tropical Convergence Zone and Hadley Cells into abnormal seasonal
positions. These effects alter the regional atmospheric circulation
systems and hydrologic cycle thereby causing drought and, as the SEAP
has intensified over time, created climate change.