Study finds Southern Hemisphere becoming drier

Phys.org, 10/3/12

A decline in April-May rainfall over south-east Australia is associated with a southward expansion of the subtropical dry-zone according to research published today in Scientific Reports, a primary research journal from the publishers of Nature.

CSIRO scientists Wenju Cai, Tim Cowan and Marcus Thatcher explored why autumn rainfall has been in decline across south-eastern Australia since the 1970s, a period that included the devastating Millennium drought from 1997-2009.

Previous research into what has been driving the decline in autumn rainfall across regions like southern Australia has pointed the finger at a southward shift in the storm tracks and weather systems during the late 20th century. However, the extent to which these regional rainfall reductions are attributable to the poleward expansion of the subtropical dry-zone has not been clarified before now.

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