Projected change in Frequency, Intensity and Duration of Atmopsheric Temperature Inversions for Southeast Australia.
Ji, F., J.P. Evans, Y. Scorgie, N. Jiang, D. Argueso and A. Di Luca
In Weber, T., McPhee, M.J. and Anderssen, R.S. (eds) MODSIM2015, 21st International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand, December 2015, pp. 490–496. ISBN: 978-0-9872143-5-5, 2015.
Temperature inversions occur when temperature increases with altitude in the lower
atmosphere. An inversion can lead to pollution events such as smog being trapped close to the ground, with
possible adverse effects on health, and may result in violent thunderstorm and freezing rain in the cold
season. The effect of temperature inversions means that any trends in their frequency, intensity (temperature
gradient within the inversion layer), and duration under global warming have implications for sectors such as
air pollution management or agriculture.
In this study, we used outputs of 12 historical and future Regional Climate Model (RCM) simulations (each
covering three time periods: 1990-2009, 2020-2039, and 2060-2079) from the NSW/ACT Regional Climate
Modelling (NARCliM) project to investigate changes in low level temperature inversions. For each 10km by
10km grid cell within the NARCliM domain, temperature inversions were identified by checking the vertical
temperature profile in 3-hourly data. Characteristics of the inversions such as height, temperature at the top
and bottom of the inversion layer were recorded. Temperature inversions for the two future periods (2020-
2039 and 2060-2079) are compared to the historic period (1990-2009) to investigate the changes in
frequency, intensity, and duration of inversions for each of the 12 simulations.
The results show that there is a substantial increase in the frequency and duration of temperature inversions
and a decrease in the intensity of the temperature inversion for most simulations for southeast Australia. The
largest differences between simulations were associated with the driving GCMs, suggesting that the large
scale circulation plays a dominant role in forming and sustaining low level temperature inversions.
Figure 1. Ensemble mean frequency of temperature inversion for 1990-2009, and changes in frequency for
2020-2039 and 2060-2079 relative to 1990-2009 (unit: %).
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Last updated 31st January 2013