Southern Annular Mode (SAM)
The Southern Annular Mode (SAM) is a climate driver that occurs in the southern hemisphere affecting the strength and position of westerly winds which influence southern Australia’s weather patterns.
During a positive SAM event, the westerly winds are stronger and positioned further south, which can lead to reduced rainfall and drought conditions across southern Australia. In contrast, during a negative SAM event, the westerly winds are weaker and positioned further north, which can lead to increased rainfall and flooding across southern Australia.
The following videos explain the impact of SAM and how it behaves.