Now learn what REALLY caused the drought and the hot weather and it was NOT the Greenies' ludicrous Climate Change SCAM.The Indian Ocean Dipole (IOD)The Indian Ocean Dipole (IOD) is defined by the difference in sea surface temperature between two areas (or poles, hence a dipole) – a western pole in the Arabian Sea (western Indian Ocean) and an eastern pole in the eastern Indian Ocean south of Indonesia. The IOD affects the climate of Australia and other countries that surround the Indian Ocean Basin, and is a significant contributor to rainfall variability in this region.
Like ENSO, the change in temperature gradients across the Indian Ocean results in changes in the preferred regions of rising and descending moisture and air.
In scientific terms, the IOD is a coupled ocean and atmosphere phenomenon, similar to ENSO but in the equatorial Indian Ocean. It is thought that the IOD has a link with ENSO events through an extension of the Walker Circulation to the west and associated Indonesian throughflow (the flow of warm tropical ocean water from the Pacific into the Indian Ocean). Hence, positive IOD events are often associated with El Niño and negative events with La Niña. When the IOD and ENSO are in phase the impacts of El Niño and La Niña events are often most extreme over Australia, while when they are out of phase the impacts of El Niño and La Niña events can be diminished.
The Indian Ocean DipolePositive event:
warmer sea surface temperatures in the western Indian Ocean relative to the east
easterly wind anomalies across the Indian Ocean and less cloudiness to Australia's northwest
less rainfall over southern Australia and the Top End.
Negative event:
cooler sea surface temperatures in the western Indian Ocean relative to the east
winds become more westerly, bringing increased cloudiness to Australia's northwest
more rainfall in the Top End and southern Australia.
VIDEO: Understanding the Indian Dipole:-
https://youtu.be/J6hOVatamYsThe Southern Annular Mode (SAM)The Southern Annular Mode (SAM), also known as the Antarctic Oscillation (AAO), describes the north–south movement of the westerly wind belt that circles Antarctica, dominating the middle to higher latitudes of the southern hemisphere.
The changing position of the westerly wind belt influences the strength and position of cold fronts and mid-latitude storm systems, and is an important driver of rainfall variability in southern Australia.
In a positive SAM event, the belt of strong westerly winds contracts towards Antarctica. This results in weaker than normal westerly winds and higher pressures over southern Australia, restricting the penetration of cold fronts inland.
Conversely, a negative SAM event reflects an expansion of the belt of strong westerly winds towards the equator. This shift in the westerly winds results in more (or stronger) storms and low pressure systems over southern Australia. During autumn and winter, a positive SAM value can mean cold fronts and storms are farther south, and hence southern Australia generally misses out on rainfall. However, in spring and summer, a strong positive SAM can mean that southern Australia is influenced by the northern half of high pressure systems, and hence there are more easterly winds bringing moist air from the Tasman Sea. This increased moisture can turn to rain as the winds hit the coast and the Great Dividing Range.
In recent years, a high positive SAM has dominated during autumn–winter, and has been a significant contributor to the 'big dry' observed in southern Australia from 1997 to 2010.
Southern Annular ModePositive phase:
band of westerly winds contracts toward Antarctica
higher pressures over southern Australia
can relate to stable, dry conditions.
Negative phase:
band of westerly winds expands towards the equator
more (or stronger) low pressure systems over southern Australia
can mean increased storms and rain.
VIDEO: Understanding the Southern Annular Mode:-
https://youtu.be/KrhWsXCB3u8http://www.bom.gov.au/climate/enso/history/ln-2010-12/SAM-what.shtml