A homogenised daily temperature data set for Australia Blair Trewin and Simon Grainger Climate Information Services Australian Bureau of Meteorology
[email protected] 1. What observations are available to support long-term 2. The ACORN-SAT network and data 3. Why do we need a complex adjustment algorithm? temperature analysis in Australia? 112 locations were selected for the Australian Climate Observations Reference Network – The impact of an inhomogeneity on temperature observations is not necessarily uniform Surface Air Temperature (ACORN-SAT) network (Figure 2). 60 of these 112 locations have throughout the year. Inhomogeneities may have a seasonal cycle; for example, if a site moves The first systematic long-term temperature observations in Australia began in the mid-19th digitised daily data extending back to 1910 (in many cases, from a composite of two or more from a coastal location to one which is more continental, the impact on maximum century, although some fragmented short-term observations were made at various locations stations in close proximity to each other). A number of key stations in central Australia opened temperatures is likely to be largest during the summer when sea breezes are a more since shortly after European settlement in 1788. in the 1940s and 1950s. Much pre-1957 Australian daily temperature data remains to be significant influence. digitised, and about 20 more stations are potential candidates for addition to the data set once Until 1901, Australia was governed as six separate British colonies (each with their own their pre-1957 data are available. Figure 3 shows an example of a case where there is no significant inhomogeneity in the government agency responsible for meteorology), and the Bureau of Meteorology was not annual mean but a substantial one in seasonal values.