Trends in maximum temperatures in Australia from 1990 to 2012

Abstract

© 2020 by Maejo University, San Sai, Chiang Mai, 50290 Thailand. This study uses statistical methods to analyse climatic variations of air surface temperatures in Australia between 1990 and 2012. Maximum monthly temperature data were obtained from the Australian Bureau of Meteorology. Monthly maximum temperatures, collected from 81 stations in Australia over a period of 23 years, were analysed to determine the variation trends. The data from each station were adjusted for seasonal effects, and then further autocorrelations were removed by using a second-order autoregressive process. In the next step, factor analysis was employed to account for spatial correlations and group all stations into five regions, namely south-east, central-north, central-east, central-west and central regions. A simple linear regression model was then fitted to the data within each region. The average maximum temperatures trended higher in the south-east and central-west regions, with temperatures increasing between 0.071-0.559°C per decade. In contrast, those in the central-north region decreased from 0.004 to 0.314 °C per decade while the central and central-east regions showed insignificant increase in temperature.