Forecasting Drought in Eastern Australia

Global climatic variation has a considerable effect on regional precipitation. For example, El-Nino Southern Oscillation (ENSO) brings about unusual weather conditions to both western and eastern tropical Pacific. Eastern Australia is particularly affected by the ENSO phenomenon, which is associated with drought during the El-Nino phase. This paper investigated the association between various climatic indices, derived from the Southern Oscillation Index (SOI) record, and the multivariate distribution of drought at numerous sites in a large region of Eastern Australia. Significance testing is based on multiple comparison techniques, which allow for the large number of two site comparisons. The climate indices will include the El-Nino, neutral and La-Nina classification and also phase changes in SOI (Stone et. al., 1996), and may be lagged relative to rainfall. Two strategies for forecasting June to October rainfall are compared. The first uses the change in SOI between April and May, whereas the second uses the SOI of May. A comparison of June to October rainfall in El-Nino years is compared with that in La-Nina years.