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The characteristics of seasonal-scale droughts in Australia, 1911-2009

journal contribution
posted on 2023-05-19, 08:21 authored by Gallant, AJE, Reeder, MJ, James RisbeyJames Risbey, Hennessy, KJ
Climatologies and variations in seasonal-scale droughts in Australia are quantified using four indices representing the characteristics of the lower tails of rainfall and soil moisture distributions. These indices estimate variations in drought frequency, duration and intensity from 1911 to 2009 across Australia and for five large-scale regions. Since 1911, large interdecadal variations in the characteristics of seasonal-scale droughts have overlain trends towards less frequent, shorter and less severe droughts across much of Australia, with the strongest trends in northwest Australia. Regional exceptions include increases in seasonal-scale drought frequency, duration and intensity in areas of southwest and southeast Australia. In parts of the west and southeast of the Murray-Darling Basin, the average duration of seasonal-scale droughts, defined as successive seasons in drought, statistically significantly increased by between 10 and 69% during the second half of the 20th Century. Averaged across large-scale regions in southeast and northwest Australia, decades with longer-lasting and more intense soil moisture-based seasonal droughts had statistically significantly higher actual evaporation compared with other decades. These were combined with modest rainfall deficits, suggesting that evaporation may be an important process for regulating drought duration or intensity in these regions. However, other hydroclimatic processes that were not assessed here likely also influence soil moisture, making attribution difficult.

History

Publication title

International Journal of Climatology

Volume

33

Issue

7

Pagination

1658-1672

ISSN

0899-8418

Department/School

Institute for Marine and Antarctic Studies

Publisher

John Wiley & Sons Ltd

Place of publication

The Atrium, Southern Gate, Chichester, England, W Sussex, Po19 8Sq

Rights statement

Copyright 2012 Royal Meteorological Society

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  • Restricted

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