Discovery Of Effect Of El Ninosouthern Oscillation On Australia

India suffered a severe drought and famine during 1877. Sir Henry Blanford, the director of the Indian Meteorological Service, noted the very high atmospheric pressures over Asia at the time and requested pressure information from other meteorologists around the world. Sir Charles Todd, the South Australian government observer noted that pressures were also high during 1877 over Australia, and much of the country suffered from drought that year. Todd compared earlier droughts and concluded that Indian and Australian droughts usually coincided. This observation has since been confirmed (e.g., Williams et al., 1986) and forms part of the suite of climate linkages we now call the Southern Oscillation (SO).

4 ECOLOGICAL IMPACTS OF EL NIÑO-SOUTHERN OSCILLATION 809

When Sir Gilbert Walker named and documented the SO in the early decades of the twentieth century, its close relationship with Australian rainfall quickly became apparent (e.g., Bliss and Walker, 1932). Walker's work suggested that north Australian summer rainfall could be predicted with an index of the SO. Quayle (1910, 1929) suggested that rainfall farther south could be predicted in the same way. After that, a trickle of studies discussed the relationship between the SO and Australian climate, up to the mid-1970s, when the worldwide attention on El Niño led to a resurgence of interest among Australian meteorologists.

By the early- 1980s attention had turned to the possible use of the ENSO in prediction. Work on the physical cause of the phenomenon had commenced, and several studies describing patterns and relationships between the ENSO, sea surface temperature, and Australian climate had been published (e.g., Pittock, 1975; Streten, 1981; Coughlan, 1979). Some of the lag relationships suggested by Quayle and others had been validated and extended using new data (Nicholls and Woodcock, 1981; McBride and Nicholls, 1983). New relationships indicating that seasonal temperature, wet-season onset, and even seasonal tropical cyclone activity also were predictable, through the ENSO, had been uncovered (Nicholls, 1978, 1979; Nicholls et al., 1982). The recognition in mid-1982 that a major El Niño episode was under way led to cautious statements regarding possible implications for Australian rainfall through the remainder of 1982, based on this work (Nicholls, 1983). The Bureau's National Climate Centre began preparing and issuing regular monthly "Seasonal Climate Outlooks" in 1989, based on the SOI. These provide forecasts of 3-month rainfall anomalies, across the country.

Variables other than seasonal rainfall appear to be predictable through the use of the ENSO. For instance, Stone et al. (1996) suggest that seasonal frost forecasts could be feasible in eastern Australia. Nicholls and Kariko (1993) and Suppiah and Hennessy (1996) found that rainfall events and intensity were related to the ENSO. Whetton et al. (1990) and Allan et al. (1996) documented relationships of the ENSO with streamflow variations.

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