Chapter 1 Introduction

The Nature of Australian Climate

The geographic location of the Australian continent with respect to the large-scale global circulation, its size and, in particular, its meridional extent from the tropics well into the middle latitudes, in the predominantly oceanic southern hemisphere, combine to give Australia its wide range of climatic regimes and strong seasonality. Extremes of rainfall are common, with both droughts and floods experienced frequently, often in rapid succession as an El Niño event comes to an end. The magnitude of the rainfall variability over the last century, even at continental scales, is evident from Figure 1.4, which shows that the wettest year (1974) received more than twice the mean rainfall received in the driest year (1902), averaged across the entire country.

Figure 1.4 Mean spatially averaged Australian annual rainfall (mm) and maximum and minimum temperature from 1910 to 2002. The thin line shows the linear trend. Based on datasets from Lavery et al. (1997) and Torok et al. (1996), updated by the National Climate Centre for the period from 1993 to 2002. Della-Marta, P.M, Collins, D.A., Braganza, K. (2003)

Many publications on Australia’s climate have followed the Bureau of Meteorology’s first account of Australia’s climate in 1913 by Hunt, Taylor and Quayle. More detailed information on twentieth century Australian climate patterns is contained in the Climatic Atlas of Australia - Rainfall (Bureau of Meteorology, 2001), Climatic Atlas of Australia – Evapotranspiration (Bureau of Meteorology, 2001), Climate Averages of Australia (Bureau of Meteorology, 1988), the annual Year Book Australia (Australian Bureau of Statistics, 2001), Climate of Australia (Bureau of Meteorology, 1989) and a series of booklets, published individually by the Bureau of Meteorology, on the climates of the individual Australian states. A summary is provided in the Cambridge Encyclopedia of Australia (Bambrick, 1994).