Australian winter circulation and rainfall changes and projections
- 17 May 2011
- journal article
- research article
- Published by Emerald in International Journal of Climate Change Strategies and Management
- Vol. 3 (2), 170-188
- https://doi.org/10.1108/17568691111129002
Abstract
Purpose: Major shifts in the southern hemisphere circulation occurred during the mid‐1970s concurrent with large reductions in southern Australian winter rainfall associated with decreased cyclogenesis. The purpose of this paper is to study changes in cyclogenesis over southern Australia during the last 50 years, examine the ability of coupled climate models to simulate the winter circulation changes, and discuss projected changes in winter circulation and rainfall under different climate change scenarios.Design/methodology/approach: Three dimensional instability theory is used to study changes in cyclogenesis. The response of 22 coupled model intercomparison project three (CMIP3) IPCC climate models to observed increases in greenhouse gases, from pre‐industrial to the end of the twentieth century, is examined. The authors focus on two diagnostics closely related to the changes in cyclogenesis: changes in the 300 hPa zonal wind strength; and changes in the baroclinic instability. Projected changes in baroclinic instability and rainfall are investigated in SRESB1, SRESA1B and SRESA2 scenarios.Findings: There has been a 30 per cent reduction in the growth rate of the leading storm track mode crossing southern Australia in the 1975‐1994 period, and a 37 per cent reduction in the 1997‐2006 period, when compared to 1949‐1968. Most of the CMIP3 models capture the changes in the zonal wind; only about a third the changes in baroclinic instability. Projected changes in baroclinic instability and rainfall suggest further reductions in the growth rate of storm track modes and further large reductions in rainfall over southern Australia.Originality/value: The paper addresses a major cause of the reduction in Australian winter rainfall, and provides guidance on future‐projected changes.Keywords
This publication has 15 references indexed in Scilit:
- Severe storms inferred from 150 years of sub-daily pressure observations along Victoria's "Shipwreck Coast"Journal of Southern Hemisphere Earth System Science, 2009
- Anomalous Rainfall over Southwest Western Australia Forced by Indian Ocean Sea Surface TemperaturesJournal of Climate, 2008
- Dynamics of late autumn rainfall reduction over southeastern AustraliaGeophysical Research Letters, 2008
- Key findings from the Indian Ocean Climate Initiative and their impact on policy development in AustraliaClimatic Change, 2008
- THE WCRP CMIP3 Multimodel Dataset: A New Era in Climate Change ResearchBulletin of the American Meteorological Society, 2007
- Interdecadal changes in southern hemisphere winter storm track modesTellus A: Dynamic Meteorology and Oceanography, 2007
- Shifts in the synoptic systems influencing southwest Western AustraliaClimate Dynamics, 2006
- The ERA‐40 re‐analysisQuarterly Journal of the Royal Meteorological Society, 2005
- The NCEP/NCAR 40-Year Reanalysis ProjectBulletin of the American Meteorological Society, 1996
- Energy Transformations and Meridional Circulations associated with simple Baroclinic Waves in a two-level, Quasi-geostrophic ModelTellus, 1954