Characterising southwest Australia's rainfall variability using speleothems and climate models

Citation

Land & Water Australia. 2009. Characterising southwest Australia's rainfall variability using speleothems and climate models. [Online] (Updated June 24th, 2009)
Available at: http://lwa.gov.au/node/2985 [Accessed Tuesday 26th of April 2011 01:39:23 AM ].

Dr Pauline Treble has used chemical analysis in the layers formed on cave stalagmites to discover the prehistoric variability of Australia’s rainfall. These have then been compared with climate model’s predictions of the past.

The research is providing a deeper understanding of the speleothem record for south-western Australia and the Murray Darling Basin. Pauline’s fieldwork has recovered material suitable to know what drip water tells about the surface rainfall conditions. Although the length of the record and the overall number of speleothems available for study was less than anticipated, the analysis of the modern samples has improved the understanding of the relationships between magnesium and calcium ratios and delta Oxygen eighteen isotopes to intra- and inter-annual rainfall variations. Specifically, the likely winter sensitivity of the records and the distinct tropical cyclone signals that should be recorded in the speleothems. Pauline has published information on the sources of rainfall in the period 1930-1955 detected from the stalagmites.

Project Objectives

extend the rainfall history for South-west Western Australia by constructing paleo-rainfall records in the Swan and Southwest regions of the state.
assess the worth of the paleo records
provide State water and conservation agencies with information about the characteristics of multi-decadal scale events
assess the extent to which the characteristics of the GCM downscaled rainfall reconstructions reflect those of the paleo record
provide State agencies with downscaled rainfall reconstructions
test whether the rainfall construction techniques developed for SWWA are appropriate at the MDB site.