How extreme apparitions of the volcanic and anthropogenic south east
Asian aerosol plume simultaneously trigger and sustain: El Niño and
Indian Ocean Dipole events and drought in south eastern Australia .
First attribution and mechanism
Abstract
Volcanic aerosol plumes over south east Asia (SEAsia), and only over
SEAsia, have always been the trigger and sustaining cause of: El Niño
Southern Oscillation (ENSO) events which are the dominant mode of
variability in the global climate; Australian and Indonesian droughts;
increased global temperatures; and Indian Ocean Dipole (IOD) events. In
recent decades this natural plume has been augmented by an anthropogenic
plume which has intensified these events especially from September to
November. Understanding the mechanism which enables aerosols over
SEAsia, and only over SEAsia, to create ENSO events is crucial to
understanding the global climate. I show that the SEAsian aerosol plume
causes ENSO events by: reflecting/absorbing solar radiation which warms
the upper troposphere; and reducing surface radiation which cools the
surface under the plume. This inversion reduces convection in SEAsia
thereby suppressing the Walker Circulation and the Trade Winds which
causes the Sea Surface Temperature (SST) to rise in the central Pacific
Ocean and creates convection there. This further weakens/reverses the
Walker Circulation driving the climate into an ENSO state which is
maintained until the SEAsian aerosols dissipate and the climate system
relaxes into a non-ENSO state. Data from the Global Volcanism Program
(151 years), the Last Millennium Ensemble (1,156 years), MERRA-2 (41
years) and NASA MODIS on Terra (21 years) demonstrates this connection
with the Nino 3.4 and 1+2 SST, the Southern Oscillation Index, and three
events commonly associated with ENSO: drought in south eastern
Australia; the IOD and a warmer World.