Variability of southeastern Queensland rainfall and climate indices

Abstract

The variability of climate indices and rainfall in southeastern (SE) Queensland (Qld) is studied. Using high-resolution gridded rainfall data for all of Australia and global sea-surface temperatures (SSTs), the relationship between Australiawide rainfall (and in SE Qld in particular) and SST indices and the southern oscillation index (SOI) have been investigated. It is found that SE Qld is more subject to the breakdown of correlations between the SOI and rainfall than any other part of Australia. Model predictions suggest that this is probable in the future.Considering only time scales longer than interannual, it was found that SSTs in the central tropical Pacific Ocean (TPO; represented by the Niño-4 index) correlated best with SE Qld rainfall. Eastern TPO (Niño-3) SSTs and the SOI produced successively weaker correlations. The time series of the second modes of variability of SSTs over the Pacific and Indian Oceans were shown to have limited impact on SE Qld rainfall variability.The data were split into periods before and after 1946, when Australian mean rainfall changed. Whereas the SOI correlations with rainfall in SE Australia were similar in both periods, in SE Qld the correlations were very weak in the earlier period (0.06) but very strong in the later period (0.72). The Niño-4 index correlated better than the Niño-3 index in both periods, but both indexes showed smaller changes from the earlier to the later periods than the SOI.

Rainfall and streamflow response to El Niño Southern Oscillation: a case study in a semiarid catchment, Australia

“…The Centre for Ocean-Land-Atmosphere studies (COLA) has recently developed an anomaly coupled prediction system, using sophisticated dynamic ocean and atmosphere models that produce skilful forecasts of tropical Pacific sea-surface temperature anomalies (SSTA) up to 18 months in advance (Kirtman & Shukla, 2006). The effect of ENSO on the rainfall patterns in Australia has been described previously (Pittock, 1975;McBride & Nicholls, 1983;Allan, 1988;Lough, 1991;Murphy & Ribbe, 2004). This research has proposed the use of ENSO based streamflow forecasting systems with water managers and the irrigation community seen as prime users .…”

A possible cause of decreasing summer rainfall in northeast Australia

“…The influence of sea surface temperature (SST) in the central and eastern Pacific on Australian rainfall variability has been clearly established (e.g. McBride and Nicholls, 1983;Drosdowsky and Williams, 1991;Lau and Nath, 1996;Murphy, 2004). Previous studies have provided evidence that warm El Niño events are generally accompanied by drought conditions over northern and eastern Australia, whereas aboveaverage rainfall occurs during La Niña events.…”

“…Nicholls, 1989;Simmonds, 1990;Ashok et al, 2003;Murphy, 2004;Cai et al, 2009). Nicholls et al (1996) described an apparent change in the relationship between ENSO and Australian rainfall and temperature.…”

“…The authors ascribed the change to an increase in Indian Ocean SST, and pointed out that interannual rainfall variability is amplified in regions affected by ENSO (Nicholls 1988), such as NEA. NEA is located at the margin of monsoon-affected Australia; consequently, rainfall variability in this region is affected by atmospheric phenomena rather than by ENSO (Murphy, 2004). However, few studies have discussed the relationship between the tropical Australian summer monsoon (TASM) and NEA rainfall.…”

Impact of climate variability on an east Australian bay

“…In Australia, where climate is characterised by significant inter-annual Email addresses: graewe@icbm.de (U. Gräwe) variability in rainfall (Murphy and Ribbe 2004), longer lasting trends in annual rainfall have been observed since about 1950 (Shi et al 2008a). Along the densely populated east coast, annual rainfall has declined by more than 200 mm during the period 1951-2000.…”