raki_etal_2008.pdf (369.51 kB)
A pressure gradient metric capturing planetary-scale influences on eastern Australian rainfall
journal contribution
posted on 2023-05-16, 21:58 authored by Rakich, CS, Neil HolbrookNeil Holbrook, Timbal, BThe 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. Copyright 2008 by the American Geophysical Union.
History
Publication title
Geophysical Research LettersVolume
35Issue
8Pagination
L08713ISSN
0094-8276Department/School
School of Geography, Planning and Spatial SciencesPublisher
American Geophysical UnionPlace of publication
United StatesRepository Status
- Restricted