Was the risk of the record-breaking Australian heat wave in 2013 increased by human activity?

The Australian summer of 2013 was the hottest on record, with new maximum temperature records set across the continent. This included Australia's hottest areal-averaged daily temperature, at 40.3oC. The beginning of the season was characterized by a heat wave during December 2012 and January 2013, which was remarkable due to its spatial extent and temporal persistence. By employing the fraction of attribution risk methodology, Lewis and Karoly (2013) demonstrated it is very likely that anthropogenic activity increased the likelihood of an Australian summer as extreme as 2013 by at least 2.5 times. Their work, however, concentrated on seasonal areal-mean temperatures spanning December-February. Using the heat wave framework outlined by Perkins and Alexander (2013), this study will quantify any changes in the likelihood of the record-breaking heat wave due to anthropogenic activity. Specifically, this will be performed at the daily timescale and assess changes in the probability of various heat wave characteristics, including amplitude, duration and the total number of heat wave days. The study will be undertaken by employing the gridded Australian Water Availability Project (AWAP) dataset (Jones et al., 2009) where observed events will be measured; and projections from physical climate models, where the control (historical) experiments are used to represent the absence (presence) of human influence.

References

Jones, D. A., W. Wang, and R. Fawcett, 2009: High-quality spatial climate data-sets for Australia. Australian Meteorological and Oceanographic Journal, 58, 233-248.

Lewis, S. C. and D. J. Karoly, 2013: Anthropogenic contributions to Australia's record summer temperatures of 2013, Geophys. Res. Lett., 40, doi:10.1002/grl.50673.

Perkins, S. E. and L. V. Alexander, 2013: On the Measurement of Heat Waves. J. Climate, 26, 4500–4517. doi: http://dx.doi.org/10.1175/JCLI-D-12-00383.1