Southeastern Australia has been subject to several severe, long-term droughts during the past century, including the "Federation" drought (1895-1900), the "World War II" drought (1937-1945), and the "Big Dry" (1997 to present). All three droughts were widespread and devastating, but until now the causes and nature of these three droughts had not been compared. Verdon-Kidd and Kiem highlight the differences in the nature and causes of these three droughts.
The researchers find that the droughts exhibited different severity, spatial extent, and seasonality. In addition, the three droughts resulted from different climate modes: The El Niño-Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO) were the primary drivers of the Federation drought; the Southern Annular Mode (SAM) and ENSO were major causes of the Big Dry; and a combination of Indian Ocean, ENSO, and SAM was a causal factor of the World War II drought.
The authors note that most attempts at forecasting droughts have focused on ENSO as a primary driver; the new results indicate that planners and drought managers should take into account other climate modes and their interactions when predicting drought conditions.
The research is published in Geophysical Research Letters. Authors include Danielle C. Verdon-Kidd and Anthony S. Kiem: School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
- Verdon-Kidd et al. Nature and causes of protracted droughts in southeast Australia: Comparison between the Federation, WWII, and Big Dry droughts. Geophysical Research Letters, 2009; 36 (22): L22707 DOI: 10.1029/2009GL041067
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