A pressure gradient metric capturing planetary-scale influences on eastern Australian rainfall
Article first published online: 25 APR 2008
Copyright 2008 by the American Geophysical Union.
Geophysical Research Letters
Volume 35, Issue 8, April 2008
How to Cite
2008), A pressure gradient metric capturing planetary-scale influences on eastern Australian rainfall, Geophys. Res. Lett., 35, L08713, doi:10.1029/2007GL032970., , and (
- Issue published online: 25 APR 2008
- Article first published online: 25 APR 2008
- Manuscript Accepted: 21 MAR 2008
- Manuscript Revised: 7 FEB 2008
- Manuscript Received: 11 DEC 2007
- Australian rainfall variability;
- geostrophic winds;
- Southern Annular Mode
 The Gayndah-Deniliquin index (GDI), a measure of the north-south atmospheric pressure gradient across eastern Australia, is presented. The 113 year long GDI record reveals strong interannual to decadal scale variability in zonal geostrophic wind flow across eastern Australia. The GDI, as a measure of easterly geostrophic wind strength and associated moisture transport from the Pacific Ocean, is shown to be significantly correlated with summer rainfall over vast areas of the Australian continent, especially over the Murray Darling Basin and the state of New South Wales. The latest abrupt decline in the GDI, which commenced around 2001, corresponded with the onset of a severe prolonged drought across eastern Australia. We demonstrate that the northern and southern poles of the MSLP derived GDI are differentially influenced by El Niño-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). Understanding the effects of these interactions between SAM and ENSO on moisture transport to eastern Australia could have implications for future Australian climate variability and climate change.