Relationships between the El-Niño Southern Oscillation and spate flows in southern Africa and Australia
1Centre for Applied Modelling in Water Engineering, School of Civil and Environmental Engineering, University of Adelaide, Adelaide 5005, Australia
2School of Mathematical Sciences, University of Adelaide, Adelaide 5005, Australia
3School of Engineering, University of Newcastle, Callaghan 2308, Australia
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Abstract. The flow records of arid zone rivers are characterised by a high degree of seasonal variability, being dominated by long periods of very low or zero flow. Discrete flow events in these rivers are influenced by aseasonal factors such as global climate forcings. The atmospheric circulations of the El-Niño Southern Oscillation (ENSO) have been shown to influence climate regimes across many parts of the world. Strong teleconnections between changing ENSO regimes and discharges are likely to be observed in highly variable arid zones. In this paper, the influence of ENSO mechanisms on the flow records of two arid zone rivers in each of Australia and Southern Africa are identified. ENSO signals, together with multi-decadal variability in their impact as identified through seasonal values of the Interdecadal Pacific Oscillation (IPO) index, are shown to influence both the rate of occurrence and the size of discrete flow episodes in these rivers.
Keywords: arid zones, streamflow, spates, climate variability, ENSO, Interdecadal Pacific Oscillation, IPO